Display device

Abstract

To provide a display device capable of performing a convergence adjustment and a diopter adjustment.SOLUTION: A display device includes a display optical system 1000 configured to introduce display light from a display surface of a display element 1400 provided each for a right eye and for a left eye, to a pupil surface SP. The display optical system includes, sequentially arranged from a pupil surface side to a display surface side, a first transmission reflection surface A and a second transmission reflection surface C. The display device includes an adjustment mechanism configured to change at least one of: a first interval between the first transmission reflection surface and the second transmission reflection surface; and a second interval between the pupil surface and the display surface. The adjustment mechanism includes an adjustable range capable of both a convergence adjustment performed by changing the first interval and a diopter adjustment performed by changing the first or second interval.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a display device such as a head-mounted display (HMD). [Background technology]

[0002] As an example of such a display device, Patent Document 1 discloses a display device that has a focus adjustment mechanism that shifts a lens and a display element, and that allows diopter adjustment within a range of −5D (diopters) to +2D. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7103566 Summary of the Invention [Problem to be solved by the invention]

[0004] Display devices are required to be able to perform not only diopter adjustment but also adjustment to resolve vergence-accommodation conflict (vergence adjustment: hereinafter also referred to as VAC adjustment). [Means for solving the problem]

[0005] A display device according to one aspect of the present invention includes display optical systems, each provided for the right eye and the left eye, that guide display light from a display surface of a display element to a pupil plane. The display optical system includes a first transmissive-reflective surface and a second transmissive-reflective surface, arranged in this order from the pupil plane side to the display surface side. The display device includes an adjustment mechanism that changes at least one of a first distance between the first transmissive-reflective surface and the second transmissive-reflective surface and a second distance between the pupil plane and the display surface. The adjustment mechanism has an adjustment range that allows both convergence adjustment by changing the first distance and diopter adjustment by changing the first or second distance. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a display device that can perform both convergence adjustment (VAC adjustment) and diopter adjustment. [Brief explanation of the drawings]

[0007] [Figure 1] 3A and 3B are a cross-sectional view and an aberration diagram of the display optical system of the first embodiment when not adjusted. [Figure 2] 3A and 3B are partial enlarged views of the display optical system according to the first embodiment, showing the relationship between the light-emitting position on the display element and the output angle, and the optical path. [Figure 3] 4A and 4B are a cross-sectional view and aberration diagrams of the display optical system of Example 1 during −4D adjustment. [Figure 4] 4A and 4B are a cross-sectional view and aberration diagrams of the display optical system of Example 1 when adjusted to −8D. [Figure 5] 4A and 4B are a cross-sectional view and aberration diagrams of the display optical system of Example 1 during +2D adjustment. [Figure 6] 4A and 4B are a cross-sectional view and aberration diagrams of the display optical system of Example 1 when adjusted to −10D. [Figure 7] FIG. 10 is a cross-sectional view of the display optical system of the second embodiment when not adjusted. [Figure 8] FIG. 10 is a cross-sectional view of the display optical system of the third embodiment when not adjusted. [Figure 9] 10A and 10B are a cross-sectional view and aberration diagrams of the display optical system of Example 3 during −4D adjustment. [Figure 10] 10A and 10B are a cross-sectional view and aberration diagrams of the display optical system of Example 3 when adjusted to −8D. [Figure 11] FIG. 10 is a cross-sectional view of the display optical system of the fourth embodiment when not adjusted. [Figure 12] 10A and 10B are cross-sectional views and aberration diagrams of the display optical system of Example 4 during −4D adjustment. [Figure 13] 10A and 10B are cross-sectional views and aberration diagrams of the display optical system of Example 4 when adjusted to −8D. [Figure 14] FIG. 1 is a perspective view of an HMD equipped with the display optical systems of Examples 1 to 4. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, prior to the specific description of embodiments 1 to 4, matters common to all embodiments will be described.

[0009] The HMD as a display device in each embodiment has a display element provided for each right eye and a display optical system that guides display light from the display surface of the display element to a pupil plane, which serves as an observation plane, and displays an enlarged version of the original image displayed on the display surface.

[0010] Among the display optical systems in each embodiment, the first-class optical system has two transmissive-reflective surfaces (a first transmissive-reflective surface and a second transmissive-reflective surface) that function as both transmissive and reflective surfaces, arranged in this order from the pupil plane side to the display surface side. The second-class optical system has a first optical system (pupil plane-side optical system), a second optical system (transmissive-reflective optical system), and a third optical system (panel-side optical system), arranged in this order from the pupil plane side to the display surface side. The second optical system includes two transmissive-reflective surfaces (a first transmissive-reflective surface and a second transmissive-reflective surface) and is an optical system sandwiched between them. The first optical system is an optical system sandwiched between the pupil plane and the first transmissive-reflective surface. The third optical system is an optical system sandwiched between the second transmissive-reflective surface and the display element. The first optical system and the third optical system may not exist.

[0011] The display devices of Examples 1 to 4 will be specifically described below. [Example]

[0012] 1A shows the configuration of a display optical system 1000 for one eye in an HMD according to Example 1. The display optical system 1000 has a pupil plane side optical system (first optical system) 1100 and a transmission / reflection optical system (second optical system) 1200.

[0013] The pupil plane side optical system 1100 has a first lens 1101 as a first optical element, and the transmission / reflection optical system 1200 has a second lens 1201 as a second optical element. In this way, the pupil plane side optical system 1100 and the transmission / reflection optical system 1200 each have one optical element (1101, 1201) that refracts, reflects, or diffracts light rays.

[0014] 2(A) shows an enlarged view of a portion of the display optical system 1000. The first lens 1101 has three optical surfaces, and the second lens 1201 has two optical surfaces. The optical surfaces of the first lens 1101 are referred to as the R1 surface, the R2 surface, and the R3 surface from the pupil plane side. The optical surfaces of the second lens 1201 are referred to as the R1 surface and the R2 surface from the pupil plane side.

[0015] The R2 surface of the first lens 1101 is a diffractive surface formed on a flat base surface, and the R3 surface is a curved surface. The R1 surface is a flat surface formed by applying a resin material to the R2 surface. The R1 and R2 surfaces of the second lens 1201 are both curved surfaces.

[0016] Display light from the panel unit 1400 including the display element is reflected once each by the first transmission-reflection surface and the second transmission-reflection surface of the transmission-reflection optical system 1200, passes through the transmission-reflection optical system 1200, and then passes through the pupil-plane-side optical system 1100 toward the pupil plane SP. This allows the observer to observe a virtual image (display image) of the original image displayed on the display element through their eye, which is located at the pupil plane SP where the exit pupil of the display optical system 1000 is located. At this time, light that follows the optical path for forming the display image is referred to as display light, and the rest is referred to as unwanted light. Furthermore, in this embodiment (and other embodiments described later), the pupil plane SP is the position of the entrance pupil of the observer's eye, not the vertex of the cornea of ​​the eye.

[0017] FIG. 1B shows the longitudinal aberrations (spherical aberration, astigmatism, distortion, and chromatic aberration) of the display optical system 1000 in this embodiment when the eye relief is 12 mm and a virtual image is displayed at infinity from the pupil plane SP. The eye relief is the distance on the optical axis (hereinafter simply referred to as on-axis) from the pupil plane SP to the lens surface of the pupil-plane-side optical system 1100 closest to the pupil plane. The longitudinal aberrations shown here are those observed by an eye with 0 D (diopters) of visual acuity. The maximum half angle of view is assumed to be 50°. Furthermore, FIG. 1B shows the longitudinal aberrations when the panel unit 1400 is used as the image plane in the reverse optical path (reverse tracing) from the pupil plane SP to the panel unit 1400, rather than the forward optical path (forward tracing) from the panel unit 1400 to the pupil plane SP. The longitudinal aberrations in the reverse tracing correspond to the longitudinal aberrations in the forward tracing.

[0018] In the spherical aberration diagrams, Fno indicates the F-number, the solid line indicates the spherical aberration at the reference wavelength, the d-line (wavelength 587.6 nm), the two-dot chain line indicates the spherical aberration at the g-line (wavelength 435.8 nm), and the one-dot chain line indicates the spherical aberration at the C-line (wavelength 656.3 nm). In the astigmatism diagrams, the solid line S indicates the astigmatism at the sagittal image plane, and the dashed line M indicates the astigmatism at the meridional image plane. The distortion aberration diagrams show the distortion aberration at the d-line. The chromatic aberration diagrams show the chromatic aberration of magnification at the g-line and C-line. These aberration diagrams show that the display optical system 1000 of this embodiment has good imaging performance.

[0019] Furthermore, the specifications of the polarizing elements, such as the polarizing plate, quarter-wave plate, and polarization-selective transmission / reflection element, which will be described later, are uniformly set to a thickness of 0.5 mm, a refractive index at the d-line of 1.52, and an Abbe number based on the d-line of 64, but the actual specifications may differ from these.

[0020] 2(C) shows the direction and polarization state of display light passing through each surface in the display optical system 1000. The panel unit 1400 has a display element (light modulation element) such as a liquid crystal display element or an organic EL element, a polarizing plate E, and a second quarter-wave plate D. The shape of the display element is a square with a diagonal of 1.6 inches (each side is 28.7 mm). The display element, polarizing plate E, and second quarter-wave plate D are arranged close to each other in this order toward the pupil plane.

[0021] The display light emitted from the display element as unpolarized light is converted into linearly polarized light by the polarizing plate E. This linearly polarized light is then converted into circularly polarized light by the second quarter-wave plate D, and the circularly polarized light is directed toward the transmission / reflection optical system 1200. The polarizing plate E may be configured integrally with the display element. For example, many liquid crystal display elements include a polarizing plate in their configuration, and polarizing plates are sometimes used in organic EL elements for the purpose of anti-reflection. In this case, the light emitted from the display element becomes linearly polarized. In this case, there is no need to provide a separate polarizing plate E.

[0022] The transmission-reflection optical system 1200 has a transmission-reflection film (half mirror) C as a second transmission-reflection member having a second transmission-reflection surface, a first quarter-wave plate B, a second lens 1201, and a polarization-selective transmission-reflection element A as a first transmission-reflection member having a first transmission-reflection surface.

[0023] The transflective film C is formed of a dielectric multilayer film or a metal film, and is vapor-deposited on the R2 surface of the second lens 1201. The first quarter-wave plate B is arranged so that its slow axis is inclined at 90° with respect to the slow axis of the second quarter-wave plate D, and is also inclined at 45° with respect to the polarization transmission axis of the polarizing plate E. The first quarter-wave plate B is adhered to the R1 surface of the second lens 1201.

[0024] The polarization-selective transmission-reflection element A is an element that reflects linearly polarized light in the same polarization direction as when it passed through the polarizing plate E and transmits linearly polarized light in a polarization direction perpendicular to the polarized light, and is configured, for example, by a wire grid polarizer or a laminated birefringent film polarizer. An example of a wire grid polarizer is the "WGF" manufactured by Asahi Kasei Corporation, and the wire grid-formed surface functions as the transmission-reflection surface. In this example, the polarization-selective transmission-reflection element A is bonded to the R2 surface of the first lens 1101 of the pupil plane-side optical system 1100.

[0025] Each transmissive-reflective member includes a transmissive-reflective surface, is an integral member with the transmissive-reflective surface, has almost no refractive power, and is primarily responsible for optical functions other than refraction (such as absorption according to the polarization state, change in the polarization state, and anti-reflection) and mechanical functions (such as adhesion and protection). In this embodiment, the polarization-selective transmissive-reflective element A corresponds to the first transmissive-reflective member, and the transmissive-reflective film C corresponds to the second transmissive-reflective member. Each transmissive-reflective member may be composed of a series of members with multiple functions. The thickness of the transmissive-reflective member is 0.5 mm or less or 1 mm or less. Because the transmissive-reflective film C is a thin film, it is omitted from the figures and from the numerical examples described below.

[0026] The display light incident on the transflective film C passes through it and is converted by the first quarter-wave plate B into linearly polarized light with the same polarization direction as when it passed through the polarizer E, and then enters the polarization-selective transflective element A. This linearly polarized light is reflected by the polarization selectivity of the polarization-selective transflective element A. The display light reflected by the polarization-selective transflective element A is converted by the first quarter-wave plate B into circularly polarized light with the same rotation as when it was first converted into circularly polarized light by the second quarter-wave plate D, and then enters the transflective surface C, where it is reflected.

[0027] The display light reflected by the transflective film C becomes circularly polarized light in the opposite direction to the light before reflection, enters the first quarter-wave plate B again, and is converted into linearly polarized light with a polarization direction perpendicular to the polarization direction when the light first passed through the polarizer E, and then enters the polarization-selective transflective element A. This linearly polarized light is transmitted by the polarization-selective transflective element A and directed to the pupil plane SP. In this way, the display optical system 1000 employs a triple-path design that folds the optical path twice, thereby enabling it to display a sufficiently enlarged display image despite its compact configuration.

[0028] [VAC Adjustment (Congestion Adjustment)] By providing parallax to the displayed image observed through display optical systems provided for each of the observer's left and right eyes, the observer can experience a sense of three-dimensionality. The gaze points of both eyes (the convergence position of the line of sight) differ depending on whether the observer directs their gaze in front of or behind the displayed image, but if the display optical system does not have a focus adjustment mechanism, the focus positions of both eyes will remain unchanged. If the convergence position and the focus positions of each eye do not match, this is undesirable as it causes fatigue and discomfort to the observer. For this reason, it is desirable to be able to perform VAC adjustment, which is a focus adjustment that matches the displayed image and the convergence position.

[0029] In VAC adjustment, the amount by which the focus position is corrected (focus adjustment amount) changes depending on the displayed image and the observer's point of gaze, which can change rapidly, so automatic adjustment is necessary. As for the VAC adjustment range, if it can be adjusted from at least infinity (equivalent to 0D) to the 250mm position (equivalent to -4D), this is sufficient for VAC adjustment in response to changes in the normal displayed image and the observer's point of gaze.

[0030] When a focus adjustment mechanism that drives an optical element is employed, it is preferable to reduce the drive amount of the optical element in order to perform focus adjustment at high speed. To this end, the VAC adjustment mechanism changes the distance (first distance) between the two transmissive-reflective surfaces. This makes it possible to utilize the return of the optical path and obtain a large focus adjustment amount with a small drive amount. A focus adjustment mechanism that does not change the distance between the two transmissive-reflective surfaces requires a large drive amount to obtain the same focus adjustment amount. As a result, in order to perform focus adjustment at high speed, the VAC adjustment mechanism needs to be enlarged, which undesirably leads to increased weight and power consumption.

[0031] [Diopter adjustment] In a display optical system, it is also necessary to consider the visual acuity (nearsightedness or farsightedness) of the observer's eye placed on the pupil plane. If vision correction with glasses is assumed, it is necessary to ensure a sufficient eye relief (usually 18 mm or more) to allow the glasses to be placed. In a display optical system, the effective diameter Φ of the light beam on the pupil-facing surface (exit surface) facing the pupil plane is calculated using the maximum half angle of view θmax and the eye relief L as follows: Φ≒2Ltanθmax+Δ where Δ is a margin that takes into account the effects of pupil diameter and tolerances, and is approximately 10 mm. Considering the importance of reducing size and weight in display optical systems, a configuration with an excessively large eye relief is not desirable. For this reason, it is desirable to have a configuration that allows focus adjustment (diopter adjustment) to suit the observer's eyesight without the need for eyeglasses.

[0032] The effective beam diameter is the diameter of the range through which display light from the display element can pass. Within this effective beam diameter, high-precision processing of the pupil-facing surface is required to ensure optical performance.

[0033] Considering the diverse visual acuity of observers, it is sufficient if the diopter adjustment can be performed within an adjustment range of 0D to -4D, and generally satisfactory focus adjustment can be performed even for observers with farsightedness or severe myopia.

[0034] The diopter adjustment only needs to be performed once when the viewer wears the display device on his / her head. Therefore, the diopter adjustment does not need to be automatic, and there is no need to reduce the drive amount. Therefore, what is changed by the diopter adjustment mechanism is not limited to the distance between the two transmissive-reflective surfaces. In other words, for example, the panel unit 1400 may be driven to change the distance (second distance) between the pupil plane and the display surface.

[0035] Furthermore, since the diopter adjustment mechanism can be constructed more simply than the VAC adjustment mechanism, the diopter adjustment mechanism does not become larger even if the drive amount increases, and increases in weight are unlikely to become a problem.

[0036] [Configuration of this Example] This embodiment has a VAC adjustment mechanism as an automatic adjustment mechanism that automatically drives the second lens 1201 having a second transmissive-reflective surface (transmissive-reflective film C) to perform focus adjustment, making it possible to perform VAC adjustment in response to changes in the displayed image or the observer's point of gaze. Furthermore, this embodiment also has a diopter adjustment mechanism as a manual adjustment mechanism that manually drives the second lens 1201 by the observer to perform focus adjustment, making it possible to perform diopter adjustment as a focus adjustment to suit the observer's eyesight. In other words, the display device of this embodiment has an automatic adjustment mechanism and a manual adjustment mechanism that can perform VAC adjustment and diopter adjustment, respectively.

[0037] Figure 3(A) shows the optical path of the display optical system 1000 when diopter adjustment is performed for an observer with -4D (nearsightedness) (-4D adjustment), and Figure 3(B) shows the longitudinal aberration at that time. Figure 4(A) shows the optical path of the display optical system 1000 when diopter adjustment is performed for an observer with -4D vision and VAC adjustment is performed at the 250mm position (equivalent to -4D) (-8D adjustment combined with diopter adjustment), and Figure 4(B) shows the longitudinal aberration at that time. These figures show that sufficiently good imaging performance is obtained even when diopter adjustment and VAC adjustment are performed.

[0038] In this way, by providing a VAC adjustment mechanism that adjusts the distance between the first transmission-reflection surface and the second transmission-reflection surface and a diopter adjustment mechanism, it is possible to perform diopter adjustment and VAC adjustment simultaneously.

[0039] [Expanded adjustment range] Furthermore, in order to enable diopter adjustment to accommodate the visual acuity of many observers and reduce fatigue due to convergence conflict, it is desirable that the diopter adjustment range be +2D to -5D and the VAC adjustment range be from infinity (equivalent to 0D) to the 200mm position (equivalent to -5D).

[0040] Fig. 5(A) shows the optical path of the display optical system 1000 when diopter adjustment is performed for an observer with +2D (hyperopia) vision (at +2D adjustment), and Fig. 5(B) shows the longitudinal aberration at that time. Fig. 6(A) shows the optical path of the display optical system 1000 when diopter adjustment is performed for an observer with -5D (myopia) vision and VAC adjustment is performed at the 200mm position (equivalent to -5D) (at -10D adjustment combined with diopter adjustment), and Fig. 6(B) shows the longitudinal aberration at that time. These figures show that sufficiently good imaging performance is obtained even when diopter adjustment and VAC adjustment are performed over a wide adjustment range.

[0041] [Optical definition of focus adjustment] From the perspective of optical performance, a focused state refers to a state in which the meridional and sagittal image planes are within ±1 mm in the range from the on-axis angle of view to an angle of view equivalent to 70% of the maximum half angle of view in the reverse optical path (reverse tracing) described above. For this reason, the larger the focus adjustment range and the wider the field of view, the more difficult it becomes to achieve a focused state.

[0042] [Definition of focus adjustable] Being focus adjustable means that there is a margin for driving for focus adjustment within the focus adjustment range, and that it is possible to drive with appropriate precision and speed without interference with other components, and that the ability to adjust focus is also considered from the perspective of aspects other than optical performance. In other words, simply being able to change the optical design values ​​does not constitute focus adjustment.

[0043] Table 1 below shows the spacing between each optical element (the i-th surface and the (i+1)-th surface) in the display optical system 1000 when no diopter or VAC adjustment is performed, when +2D adjustment is performed, when -4D adjustment is performed, when -8D adjustment is performed, and when -10D adjustment is performed, along with the surface number i. d5, d10, and d13 indicate the spacing between the polarization-selective transflective element A and the first quarter-wave plate B, and d16 indicates the spacing between the transflective film C and the second quarter-wave plate D. Changing these parameters changes the first spacing between the first transflective surface and the second transflective surface. The spacing for changing the first spacing is defined as the internal spacing, and the spacing on the pupil plane side of the two internal spacings (i.e., d5, d10, and d13) is defined as the first internal spacing on the pupil plane side.

[0044] The focal length ft of the entire display optical system 1000, including the diopter on the pupil plane, is also shown. Furthermore, the focal length fe2 of the transmitted light path from the first internal spacing on the pupil plane side to the pupil plane SP on the pupil plane side (downstream), the focal length fe1 of the transmitted light path from the first transmissive-reflective member to the pupil plane SP on the pupil plane side (downstream), and the focal length fr1 at the time of reflection by the first transmissive-reflective member are also shown. In other words, the focal length fe2 is the focal length of the transmitted light path up to the first internal spacing on the pupil plane side when traced back from the pupil plane, and the focal length fe1 is the focal length of the transmitted light path up to just before the first transmissive-reflective member when traced back from the pupil plane.

[0045] [Table 1]

[0046] As shown in Figure 2(A), the light emission position y on the display element of the display light with a half angle of view θ toward the pupil plane SP changes during focus adjustment. In other words, the magnification of the displayed image fluctuates during focus adjustment. If this magnification fluctuation is large, the displayed image will appear unnatural, so image processing must be performed to correct the magnification fluctuation on the displayed image (original image). However, even with image processing, the displayed image will still be missing or the resolution will deteriorate, so the amount of magnification fluctuation that can be corrected by image processing is generally within ±10%.

[0047] The light emission position y is proportional to the focal length ft of the entire display optical system 1000, including the diopter on the pupil plane. When the focal lengths ft of the entire display optical system 10000, including the diopter when no adjustment is performed and when adjusted to -8D, are ft[0D] and ft[-8D], respectively, 0.90≦ft[-8D] / ft[0D]≦1.10 It is preferable to satisfy the following conditions.

[0048] It is more preferable that the amount of magnification fluctuation that can be corrected is within ±5%. 0.95≦ft[-8D] / ft[0D]≦1.05 It is preferable to satisfy the following conditions.

[0049] In this example, from Table 1, ft[0D]=19.026mm ft[-8D]=18.778mm Therefore, ft[-8D] / ft[0D]=0.987 and the above conditions are satisfied.

[0050] Furthermore, in this embodiment, both the VAC adjustment mechanism and the diopter adjustment mechanism drive the second lens 1201. This configuration has the advantages of monotonically suppressing fluctuations in optical performance and simplifying the configuration for holding and driving the second lens 1201.

[0051] Furthermore, in this embodiment, since a diopter adjustment mechanism is provided, no space is required for placing eyeglasses, and the eye relief can be made 15 mm or less.

[0052] As described above, the effective diameter Φ of the light beam on the pupil-facing surface of the display optical system is Φ≈2L tan θmax+Δ.

[0053] In this embodiment, Eye relief L=12mm Maximum half angle of view θmax=50° Δ≒10mm twist, Effective beam diameter on the pupil-facing surface Φ≒38.6mm Since the effective beam diameter Φ of the pupil-facing surface of a typical wide-field display optical system is 50 mm or more, it can be seen that by shortening the eye relief as in this embodiment, the size of the display optical system 1000 can be significantly reduced. This downsizing directly affects the weight of the lenses and lens barrel, which leads to the advantages of simplifying the configuration of the focus adjustment mechanism and reducing the burden on the observer. Conversely, since having two focus adjustment mechanisms, a VAC adjustment mechanism and a diopter adjustment mechanism as in this embodiment, tends to result in a large weight, a light-weight display optical system with an effective beam diameter Φ of less than 50 mm at the pupil-facing surface is preferred.

[0054] In this embodiment, the nominal maximum half angle of view is assumed to be 50°. Specifically, the maximum angle of the chief ray of the display light passing through the pupil plane SP (the ray passing through the center of the pupil plane SP) is set to 50°.

[0055] Generally, if the maximum half angle of the display light's chief ray is 30° or more, it can be said to have a wide field of view, the range of stereoscopic vision is wide, and the effect of VAC adjustment is easy to realize. Conversely, if the maximum half angle of view is less than 30°, the range of stereoscopic vision is narrow, and it is difficult to obtain the effect of VAC adjustment.

[0056] If the ray angle α (see FIG. 2A) of the chief ray of the maximum half angle of view, which travels toward the pupil plane SP and passes through the first internal space on the pupil plane side, is large, the position where the ray passes on the transmissive-reflective surface during VAC adjustment will change significantly, which is undesirable because it increases the size of the transmissive-reflective surface required and increases the fluctuation in optical performance. Ray angle α<maximum half angle of view θmax Specifically, when the focal length fe2 of the transmitted light path from the second transmissive reflecting member to the pupil plane SP on the pupil plane side without adjustment is fe2[0D], 1.0≦fe2[0D] / ft[0D]≦10.0 It is preferable to satisfy the following condition. The upper limit of this condition means that the optical path from the first internal spacing on the pupil plane side to the pupil plane SP on the pupil plane side has a positive power equivalent to 10% or more of the power of the entire display optical system 1000. The lower limit of this condition means that the optical path from the first internal spacing on the pupil plane side to the pupil plane SP on the pupil plane side has a positive power equivalent to the power of the entire system. If the lower limit is not satisfied, the power balance will be poor, which is undesirable in terms of optical performance (optical aberration).

[0057] It is more preferable that the transmission optical path from the first internal spacing on the pupil plane side to the pupil plane SP on the pupil plane side has a positive power equivalent to 15% or more of the power of the entire system. 1.0≦fe2[0D] / ft[0D]≦6.6 It is more preferable that the following conditions be satisfied:

[0058] In this example, from Table 1, ft[0D]=19.026mm fe2[0D]=110.401mm Therefore, fe2[0D] / ft[0D]=5.803 and the above conditions are satisfied.

[0059] The power of the transmitted light path from the first internal spacing on the pupil plane side to the pupil surface SP on the pupil plane side is divided into the power due to the optical surfaces included in the transmission-reflection optical system and the power due to the optical surfaces included in the pupil-plane-side optical system. The optical surfaces included in the transmission-reflection optical system are likely to affect the optical performance (optical aberrations) because they are surfaces through which light rays pass three times due to the folding back of the optical path, or they may also function as transmission-reflection surfaces. Therefore, in terms of optical performance (optical aberrations), it is preferable to utilize the flexibility of the optical surfaces included in the pupil-plane-side optical system and allocate a certain amount of power or more.

[0060] Specifically, when the focal length fe1 of the transmitted light path from the first transmitting-reflecting surface to the pupil surface SP on the pupil surface side without adjustment is fe1[0D], 1.0≦fe1[0D] / fe2[0D]≦10.0 It is preferable to satisfy the following condition. The upper limit of this condition means that the transmitted optical path from the first transmitting-reflecting surface to the pupil surface SP on the pupil surface side has positive power equivalent to 10% or more of the power of the transmitted optical path from the first internal spacing on the pupil surface side to the pupil surface SP on the pupil surface side. The lower limit means that the transmitted optical path from the first transmitting-reflecting surface to the pupil surface SP on the pupil surface side has positive power equivalent to the power of the transmitted optical path from the first internal spacing on the pupil surface side to the pupil surface SP on the pupil surface side. If the lower limit is not satisfied, the power balance will be poor, which is undesirable in terms of optical performance (optical aberration).

[0061] Furthermore, it is more preferable that the transmitted optical path from the first transmitting-reflecting surface to the pupil plane SP on the pupil plane side has a positive power equivalent to 15% or more of the power of the transmitted optical path from the first internal spacing on the pupil plane side to the pupil plane SP on the pupil plane side. 1.0≦fe1[0D] / fe2[0D]≦6.6 It is more preferable that the following conditions be satisfied:

[0062] In this example, from Table 1, fe2[0D]=110.401mm fe1[0D]=343.038 mm Therefore, fe1[0D] / fe2[0D]=3.107 and the above conditions are satisfied.

[0063] The following describes the exit angle β of the chief ray emitted from the light-emitting position y on the display surface shown in Figure 2(A) with respect to the normal to the display surface. The exit angle β is negative (-) in the direction away from the optical axis and positive (+) in the direction toward the optical axis. If the exit angle β at the maximum half angle of view is negative, the size of the display element can be reduced, which is preferable from the perspective of weight. In particular, when two focus adjustment mechanisms, a VAC adjustment mechanism and a diopter adjustment mechanism, are included as in this embodiment, the weight tends to increase, so a display optical system with a small display element size is preferable.

[0064] 2B shows the relationship between the light-emitting position y on the display element and the emission angle β when there is no adjustment of the display optical system 1000. It can be seen that the emission angle β at the maximum half angle of view is −25.2°, which is negative.

[0065] As mentioned above, VAC adjustment is performed in response to changes in the displayed image and the viewer's gaze point, and therefore requires high-speed driving. To make the VAC adjustment mechanism as small as possible, it is preferable that the weight of the driven components be small. Specifically, it is preferable that the display element is not driven, and that the driven optical elements are two or less refractive elements made of resin. In this embodiment, the VAC adjustment does not drive the panel unit 1400, but drives one refractive element made of resin, the second lens 1201, and therefore satisfies the above conditions.

[0066] Display elements are generally heavy and therefore not suitable for driving VAC adjustment. Furthermore, display elements have a more complex structure than optical elements, and therefore are not suitable for diopter adjustment, let alone VAC adjustment, in terms of durability degradation due to driving. In this embodiment, the panel unit 1400 is not driven even for diopter adjustment, and the above conditions are satisfied.

[0067] Furthermore, in this embodiment, the first lens 1101 having the pupil-facing surface (surface R1) is not driven during VAC adjustment and diopter adjustment. Driving the pupil-facing surface during VAC adjustment is not preferable because the resulting air fluctuations are transmitted to the viewer, potentially causing discomfort. Driving the pupil-facing surface during diopter adjustment is also not preferable because the eye relief differs depending on the viewer, resulting in different feelings of pressure when worn.

[0068] As mentioned above, it is preferable to have a small drive amount in VAC adjustment, but it is not preferable for the drive amount to be too small and for focus adjustment errors to become large. Specifically, when the amount of change in the distance between two transmissive-reflective surfaces during focus adjustment from infinity (equivalent to 0D) to 250 mm (equivalent to -4D) is dG, 0.5mm≦|dG|≦7.0mm It is preferable to satisfy the following conditions.

[0069] In addition, 0.5mm≦|dG|≦4.0mm It is more preferable that the following conditions be satisfied:

[0070] In this example, from Table 1, |dG|=|1.983mm-2.980mm|=0.997mm and the above conditions are satisfied.

[0071] In particular, to make it easier to satisfy |dG|≦7.0 mm, it is advisable to increase the amount of focus adjustment when changing the distance between the two transmissive-reflective surfaces. One method for doing so is to increase the absolute value of the power of the first transmissive-reflective surface and the second transmissive-reflective surface. To achieve this, it is preferable to configure the first transmissive-reflective surface to have a negative power as its power during reflection. In this case, the focal length of the entire display optical system 1000 is roughly maintained due to requirements for optical performance, so the positive power of the second transmissive-reflective surface also increases. Specifically, when the focal length fr1 during reflection of the first transmissive-reflective surface without adjustment is fr1[0D], -10.0≦fr1[0D] / ft[0D]≦0 It is preferable that the following condition be satisfied: This means that the first transmission-reflection surface has a negative power equivalent to 10% or more of the power of the entire system.

[0072] Furthermore, in order to make it easier to satisfy 0.5 mm≦|dG|, it is sufficient to prevent the negative power given to the first transmitting-reflecting surface from being too large. It is preferable to satisfy the condition -10.0≦fr1[0D] / ft[0D]≦-0.5, which means that the absolute value of the negative power of the first transmitting-reflecting surface is equal to or less than twice the absolute value of the power of the entire system.

[0073] It is preferable that the absolute value of the negative power of the first transmission-reflection surface corresponds to 15% or more of the absolute value of the power of the entire system. -6.6≦fr1[0D] / ft[0D]≦-0.5 It is preferable to satisfy the following conditions.

[0074] In this example, from Table 1, ft[0D]=19.026mm fr1[0D] = -31.316mm Therefore, fr1[0D] / ft[0D]=-1.646 and the above conditions are satisfied.

[0075] As explained above, from the perspective of weight, a smaller display element is preferable. However, taking into consideration fluctuations in optical performance (optical aberration), particularly when VAC adjustment and diopter adjustment are performed simultaneously, a somewhat larger display element is preferable.

[0076] Specifically, assuming a maximum half angle of view of 30° or more, the shape of the display surface is preferably such that the diagonal length of the square circumscribing the display surface is 1.3 inches or more (each side of the circumscribing square is 23.3 mm).

[0077] Next, we will explain the fluctuation of chromatic aberration of magnification during focus adjustment (magnification fluctuation for each color of the displayed image). Since diopter adjustment is performed infrequently, it is possible to perform image processing to correct the magnification fluctuation for each color. On the other hand, since VAC adjustment is performed frequently, performing image processing to correct the magnification fluctuation for each color increases the computational processing load, which is undesirable. Therefore, it is preferable to reduce chromatic aberration of magnification as an optical performance. Specifically, it is preferable to configure the optical elements to be driven as one or two refractive elements with an Abbe number of 50 or more based on the d-line, or two refractive elements with an Abbe number difference of 20 or more.

[0078] In this embodiment, the second lens 1201, which is a single resin refractive element with an Abbe number of 56, is driven to satisfy the above conditions.

[0079] Here, the optical element refers to an optical element having a power that causes fluctuations in lateral chromatic aberration due to driving. Optical elements with little or no power are not included in the optical element, but may be associated with the optical element.

[0080] Furthermore, when using an organic EL display, LCD, or similar display element, electrical processing may be added to the original image to correct the distortion and lateral chromatic aberration of the display optical system, depending on the amount of these. However, even after image processing to correct lateral chromatic aberration, residual correction errors may remain. Furthermore, it is difficult to correct axial chromatic aberration through image processing. For this reason, it is preferable that the optical performance of the display optical system 1000 be such that both lateral chromatic aberration and axial chromatic aberration are reduced. One method for achieving this is to provide a diffractive surface. However, because the diffraction efficiency varies depending on the angle of incidence of light rays, the diffractive surface must be provided on an optical element that is not driven by VAC adjustment or diopter adjustment.

[0081] In this embodiment, a diffractive surface is provided on the R2 surface of the first lens 1101, which is not driven by either the VAC adjustment or the diopter adjustment, and the above conditions are satisfied.

[0082] Another method, which is not adopted in this embodiment, is to provide a plurality of (for example, two) refractive elements bonded together between the two transmissive-reflective surfaces, with the difference in their Abbe numbers relative to the d-line being at least 20. This allows the display light to pass through the bonded surfaces of the two refractive elements three times, thereby enhancing the effect of reducing lateral chromatic aberration and axial chromatic aberration.

[0083] In addition, when the optical path between the two transmissive-reflective surfaces changes during VAC adjustment, a configuration in which two refractive elements are bonded together has the advantage that deterioration of optical performance (optical aberrations) other than lateral chromatic aberration and axial chromatic aberration is less likely to occur than a configuration in which the refractive elements are spaced apart. Also, a refractive element may be bonded to the optical element that is driven during VAC adjustment and diopter adjustment. [Example]

[0084] Next, a display optical system 2000 according to a second embodiment of the present invention will be described. In this embodiment, descriptions common to those in the first embodiment will be omitted. The display optical system 2000 according to this embodiment is a modification of the display optical system 1000 according to the first embodiment, and differs from the display optical system 1000 only in the configuration of the focus adjustment mechanism.

[0085] 7 shows the configuration of a display optical system 2000. The display optical system 2000 has a pupil plane side optical system (first optical system) 2100 and a transmission / reflection optical system (second optical system) 2200. The pupil plane side optical system 2100 has an optical element (first lens) 2101, and the transmission / reflection optical system 2200 has an optical element (second lens) 2201.

[0086] In this embodiment, similarly to the first embodiment, an automatic adjustment mechanism is provided as a focus adjustment mechanism that drives the optical element 2201 having the second transmissive-reflective surface (transmissive-reflective film C), and it is possible to perform VAC adjustment in response to changes in the displayed image or the observer's gaze point.

[0087] On the other hand, in this embodiment, the adjustment range of the automatic adjustment mechanism is wider than in Embodiment 1, and it is also possible to perform diopter adjustment using the automatic adjustment mechanism. That is, the display optical system 2000 of this embodiment has an automatic adjustment mechanism that can perform both VAC adjustment and diopter adjustment. The adjustment ranges of VAC adjustment and diopter adjustment are 0D to -8D or more, which corresponds to the diopter adjustment range of 0D to -4D and the VAC adjustment range of infinity (equivalent to 0D) to 250mm position (equivalent to -4D).

[0088] This has the disadvantage of making the automatic adjustment mechanism larger than in Example 1, but has the advantage of simplifying the configuration compared to when multiple adjustment mechanisms are provided. Note that the effects of VAC adjustment and diopter adjustment are the same as in Example 1, and so a description thereof will be omitted. [Example]

[0089] Next, a display optical system 3000 according to a third embodiment of the present invention will be described. In this embodiment, descriptions common to those of the first embodiment will be omitted. The display optical system 3000 according to this embodiment is a modification of the display optical system 1000 according to the first embodiment, and differs from the display optical system 1000 only in the configuration of the focus adjustment mechanism.

[0090] 8 shows the configuration of a display optical system 3000. The display optical system 3000 has a pupil plane side optical system (first optical system) 3100 and a transmission / reflection optical system (second optical system) 3200. The pupil plane side optical system 3100 has an optical element (first lens) 3101, and the transmission / reflection optical system 3200 has an optical element (second lens) 3201.

[0091] In this embodiment, as in the first embodiment, a VAC adjustment mechanism is provided, which is an automatic adjustment mechanism that drives an optical element 3101 having a second transmissive-reflective surface (transmissive-reflective film C), and it is possible to perform VAC adjustment in response to changes in the displayed image or the observer's gaze point.

[0092] On the other hand, this embodiment has a diopter adjustment mechanism, which is a manual adjustment mechanism that drives the optical element 3201 and the panel unit 3400 as a unit, and it is possible to perform focus adjustment (diopter adjustment) to suit the viewer's eyesight. In other words, the display optical system 3000 of this embodiment has an automatic adjustment mechanism and a manual adjustment mechanism that can perform VAC adjustment and diopter adjustment, respectively.

[0093] This has the disadvantage of increasing the size of the diopter adjustment mechanism compared to Example 1, but has the advantage of reducing interference between the diopter adjustment mechanism and the panel unit 3400 or its holder. Also, since the focus adjustment amount relative to the drive amount increases, there is the advantage that the drive amount of the diopter adjustment mechanism can be reduced.

[0094] Fig. 9(A) shows the optical path of the optical system 3000 when the diopter is adjusted for a person with -4D (nearsightedness) (at -4D adjustment), and Fig. 9(B) shows the longitudinal aberration at that time. Fig. 10(A) shows the optical path of the display optical system 3000 when the diopter is adjusted for a person with -4D (nearsightedness) and the VAC is adjusted to the 250mm position (equivalent to -4D) (at -8D adjustment combined with the diopter adjustment), and Fig. 10(B) shows the longitudinal aberration at that time. These figures show that sufficiently good imaging performance can be obtained even when the diopter adjustment and the VAC adjustment are performed.

[0095] Table 2 shows the spacing between each optical element (the i-th surface and the (i+1)-th surface) along with the surface number i when neither diopter nor VAC adjustment is performed, when adjusted to -4D, and when adjusted to -8D in the display optical system 3000. It also shows the focal length ft of the entire display optical system 3000, including the diopter on the pupil plane.

[0096] [Table 2]

[0097] In this example, from Table 2, ft[0D]=19.026mm ft[-8D]=18.865mm Therefore, ft[-8D] / ft[0D]=0.992 And 0.90≦ft[-8D] / ft[0D]≦1.10 The following conditions are satisfied. [Example]

[0098] Next, a display optical system 4000 according to a fourth embodiment of the present invention will be described. In this embodiment, descriptions common to those in the first embodiment will be omitted. The display optical system 4000 according to this embodiment is a modification of the display optical system 1000 according to the first embodiment, and differs from the display optical system 1000 only in the configuration of the focus adjustment mechanism.

[0099] 11 shows the configuration of a display optical system 4000. The display optical system 4000 has a pupil plane side optical system (first optical system) 4100 and a transmission / reflection optical system (second optical system) 4200. The pupil plane side optical system 4100 has an optical element (first lens) 4101, and the transmission / reflection optical system 4200 has an optical element (second lens) 4201.

[0100] In this embodiment, similar to the first embodiment, a VAC adjustment mechanism is provided, which is an automatic adjustment mechanism that drives an optical element 4201 having a second transmissive-reflective surface (transmissive-reflective film C), and it is possible to perform VAC adjustment in response to changes in the displayed image or the observer's gaze point.

[0101] On the other hand, this embodiment has a diopter adjustment mechanism, which is a manual adjustment mechanism that drives the optical element 4101, and is capable of performing focus adjustment (diopter adjustment) to suit the observer's eyesight. That is, the display optical system 4000 of this embodiment has an automatic adjustment mechanism and a manual adjustment mechanism that can perform VAC adjustment and diopter adjustment, respectively.

[0102] This has the disadvantage of making the combined size of the diopter adjustment mechanism and VAC adjustment mechanism larger than in Example 1, but has the advantage of making it easier to manufacture the display device because the diopter adjustment mechanism and VAC adjustment are separated.

[0103] Fig. 12(A) shows the optical path of the display optical system 4000 when diopter adjustment is performed for a person with -4D (nearsightedness) eyesight (at -4D adjustment), and Fig. 12(B) shows the longitudinal aberration at that time. Fig. 13(A) shows the optical path of the display optical system 4000 when diopter adjustment is performed for a person with -4D (nearsightedness) eyesight and VAC adjustment is performed to the 250mm position (equivalent to -4D) (at -8D adjustment combined with diopter adjustment), and Fig. 13(B) shows the longitudinal aberration at that time. These figures show that sufficiently good imaging performance can be obtained even when diopter adjustment and VAC adjustment are performed.

[0104] Table 3 shows the spacing between optical elements (the i-th surface and the (i+1)-th surface) along with the surface number i when neither diopter nor VAC adjustment is performed, when adjusted to -4D, and when adjusted to -8D in the display optical system 4000. It also shows the focal length ft of the entire display optical system 4000, including the diopter on the pupil plane.

[0105] [Table 3]

[0106] In this example, from Table 3, ft[0D]=19.026mm ft[-8D]=18.944mm Therefore, ft[-8D] / ft[0D]=0.996 And 0.90≦ft[-8D] / ft[0D]≦1.10 The following conditions are satisfied.

[0107] Numerical examples corresponding to Example 1 are shown below. Numerical examples of Examples 2 to 4 are the same as Numerical Example 1.

[0108] In the surface data, surface number i indicates the ith surface when counted from the pupil surface side. r is the radius of curvature of the ith surface (mm), and d is the lens thickness or air gap (mm) between the ith and (i+1)th surfaces. d is the value when no adjustment is performed. nd is the refractive index at the d-line of the material of the ith optical element. νd is the Abbe number based on the d-line of the material of the ith optical element. The Abbe number based on the d-line, νd, is given by the following when the refractive indices at the Fraunhofer d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) are Nd, NF, and NC, respectively: νd=(Nd-1) / (NF-NC) It is expressed as:

[0109] An asterisk (*) next to a surface number indicates that the surface has an aspherical shape. The aspherical shape is expressed by the following equation, where x is the displacement in the optical axis direction at a position of height h from the optical axis relative to the vertex of the surface, R is the paraxial radius of curvature, k is the conic constant, and Ai (i = 4, 6, 8, 10, ...) are the aspherical coefficients of each order.

[0110]

number

[0111] In addition, "e±XX" in the conic constant and aspherical coefficient is "×10± XX " means.

[0112] Furthermore, the phase shape F(h, m) of the diffractive optical element at a height h in the radial direction from the optical axis is expressed as follows, where m is the diffraction order, λ is the reference wavelength, and C (i is a natural number) is the phase coefficient of the 2i-th order term: F(h,m)=(2π / mλ0)(C1h2+C2h4+C3h6+…) In this case, the refractive power φ of the diffractive surface of the diffractive optical element for an arbitrary wavelength λ and an arbitrary diffraction order m is expressed by the following equation using a phase coefficient C1.

[0113] φ(λ,m)=-2C1mλ / λ0 In the diffractive optical element of this numerical example, the diffraction order m of the diffracted light is 1, and the design wavelength λ0 is the d-line (587.6 nm). [Numerical Example] Unit: mm Surface Data Surface number rd nd νd 1 (Aperture) ∞ (Variable) 2 ∞ 0.10 1.64270 40.2 3(diffraction) ∞ 2.40 1.58800 28.3 4* -95.200 0.50 1.52000 64.0 5* -95.200 (variable) 6 -400.000 0.50 1.52000 64.0 7 -400.000 6.00 1.54390 56.0 8* -52.400 -6.00 9 -400.000 -0.50 -1.52000 64.0 10 -400.000 (variable) 11* -95.200 -0.50 -1.52000 64.0 12* -95.200 0.50 13* -95.200 (variable) 14 -400.000 0.50 1.52000 64.0 15 -400.000 6.00 1.54390 56.0 16* -52.400 (variable) 17 ∞ 0.50 1.52000 64.0 Image plane ∞ Aspheric data Surface 3 (diffractive surface) C 2=-1.45757e-03 C 4=-8.94091e-07 C 6= 5.15514e-10 C 8= 1.21057e-11 C10= 6.73893e-15 Side 4 K = 0.00000e+00 A 4= 4.11683e-06 A 6= 7.69779e-09 A 8=-8.21078e-12 5th page K = 0.00000e+00 A 4= 4.11683e-06 A 6= 7.69779e-09 A 8=-8.21078e-12 Side 8 K =-1.14035e+00 Page 11 K = 0.00000e+00 A 4= 4.11683e-06 A 6= 7.69779e-09 A 8=-8.21078e-12 Side 12 K = 0.00000e+00 A 4= 4.11683e-06 A 6= 7.69779e-09 A 8=-8.21078e-12 Page 13 K = 0.00000e+00 A 4= 4.11683e-06 A 6= 7.69779e-09 A 8=-8.21078e-12 Page 16 K =-1.14035e+00 Focal length 19.03 d 1 12.00 d5 2.98 d10 -2.98 d13 2.98 d16 1.02 [Display device] 14 shows a head mounted display (HMD) 1 as a display device using the display optical systems of Examples 1 to 4. The HMD 1 is worn on the head (in front of the eyes) of a viewer by means of a wearing gear (not shown).

[0114] The HMD1 has display elements RID and LID for the right and left eyes, a right-eye display optical system ROS that guides display light from the right-eye display element RID to the observer's right eye, and a left-eye display optical system LOS that guides display light from the left-eye display element LID to the observer's left eye.

[0115] By using the display optical systems shown in Examples 1 to 4 as the right-eye and left-eye display optical systems ROS and LOS, it is possible to realize an HMD that allows the viewer to view good images.

[0116] The above embodiment includes the following configurations.

[0117] (Configuration 1) A display device having a display optical system provided for each of the right and left eyes, which guides display light from a display surface of a display element to a pupil plane, the display optical system includes a first transmissive-reflective surface and a second transmissive-reflective surface arranged in this order from a pupil plane side to a display surface side, the display device has an adjustment mechanism that changes at least one of a first distance between the first transmission-reflection surface and the second transmission-reflection surface and a second distance between the pupil plane and the display surface, The adjustment mechanism includes: A display device having an adjustment range that allows both convergence adjustment by changing the first distance and visibility adjustment by changing the first or second distance. (Configuration 2) The display device according to configuration 1, characterized in that the adjustment mechanism has an automatic adjustment mechanism that performs the convergence adjustment in accordance with the image displayed on the display surface, and a manual adjustment mechanism that performs the diopter adjustment. (Configuration 3) 3. The display device according to configuration 2, wherein the automatic adjustment mechanism and the manual adjustment mechanism are each capable of adjusting the diopter on the pupil plane from at least −4 diopters to 0 diopters. (Configuration 4) 2. The display device according to configuration 1, wherein the adjustment mechanism has an automatic adjustment mechanism that performs the convergence adjustment and the visibility adjustment in accordance with the image displayed on the display surface. (Configuration 5) 5. The display device according to configuration 4, wherein the automatic adjustment mechanism is capable of adjusting the diopter on the pupil plane from at least −8 diopters to 0 diopters. (Configuration 6) When the diopter on the pupil plane after adjustment by the adjustment mechanism is 0 diopter and −8 diopter, the focal lengths of the display optical system including the diopter are respectively ft[0D] and ft[−8D]. 0.90≦ft[-8D] / ft[0D]≦1.10 6. The display device according to configuration 3 or 5, wherein the following conditions are satisfied: (Configuration 7) The display device described in any one of configurations 1 to 6, wherein the adjustment mechanism drives the same transmissive-reflective surface of the first transmissive-reflective surface and the second transmissive-reflective surface for the convergence adjustment and the visibility adjustment. (Configuration 8) 8. The display device according to any one of configurations 1 to 7, wherein the eye relief of the display optical system is 15 mm or less. (Configuration 9) 9. The display device according to any one of configurations 1 to 8, wherein the diameter of the range through which the display light can pass on a surface of the display optical system facing the pupil plane is 50 mm or less. (Configuration 10) 10. The display device according to any one of configurations 1 to 9, wherein a maximum half angle of view formed by a chief ray of the display light passing through the pupil plane is 30° or more. (Configuration 11) When the diopter on the pupil plane after adjustment by the adjustment mechanism is 0 diopter, the focal length of the display optical system including the diopter is ft[0D], and when the diopter on the pupil plane is 0 diopter, the focal length of the transmitted light path from the first internal spacing on the pupil plane side to the pupil plane side is fe2[0D], 1.0≦fe2[0D] / ft[0D]≦10.0 11. The display device according to any one of configurations 1 to 10, wherein the following conditions are satisfied: (Configuration 12) When the diopter on the pupil plane when adjustment is performed by the adjustment mechanism is 0 diopter, the focal length of the transmitted light path from the first transmitting-reflecting surface to the pupil plane on the pupil plane side is fe1[0D], 1.0≦fe1[0D] / fe2[0D]≦10.0 12. The display device according to configuration 11, which satisfies the following conditions: (Configuration 13) 13. The display device according to any one of configurations 1 to 12, wherein an exit angle of a chief ray of the display light at a maximum half angle among the chief rays of the display light passing through the pupil plane is an angle directed away from the optical axis of the display optical system. (Configuration 14) 6. The display device according to configuration 2 or 5, wherein the automatic adjustment mechanism does not drive the display element, but drives two or less refractive elements made of resin. (Configuration 15) 3. The display device according to configuration 2, wherein the manual adjustment mechanism does not drive the display element. (Configuration 16) 16. The display device according to any one of configurations 1 to 15, wherein the adjustment mechanism does not drive an optical element in the display optical system that has an optical surface facing the pupil plane. (Configuration 17) When the diopter on the pupil plane is 0 diopter and −4 diopter, the change in the distance between the first transmissive-reflective surface and the second transmissive-reflective surface is dG, 0.5mm≦|dG|≦7.0mm 17. The display device according to any one of configurations 1 to 16, wherein the following conditions are satisfied: (Configuration 18) When the diopter on the pupil plane after adjustment by the adjustment mechanism is 0 diopter, the focal length of the display optical system including the diopter is ft[0D], and when the diopter on the pupil plane is 0 diopter, the focal length upon reflection by the first transmissive-reflective surface is fr1[0D]. -10.0≦fr1[0D] / ft[0D]≦-0.5 18. The display device according to any one of configurations 1 to 17, wherein the following conditions are satisfied: (Configuration 19) 19. The display device according to any one of configurations 1 to 18, wherein the diagonal length of a square circumscribing the display surface is 1.3 inches or more. (Configuration 20) 20. The display device according to any one of configurations 1 to 19, wherein the optical element driven by the automatic adjustment mechanism is composed of one or two refractive elements having an Abbe number of 50 or more based on the d-line, or two refractive elements having an Abbe number difference of 20 or more based on the d-line. (Configuration 21) the display optical system has an optical element that is not driven by the adjustment mechanism, 21. The display device of any one of configurations 1 to 20, wherein the optical element has a diffractive surface. (Configuration 22) 22. The display device according to any one of configurations 1 to 21, characterized in that a plurality of refractive elements are bonded to each other between the first transmissive-reflective surface and the second transmissive-reflective surface, the difference between their Abbe numbers based on the d-line being 20 or more. (Configuration 23) 23. The display device according to any one of configurations 1 to 22, wherein the display optical system guides the display light to the pupil plane via transmission at the second transmission-reflection surface, reflection at the first transmission-reflection surface, reflection at the second transmission-reflection surface, and transmission at the first transmission-reflection surface.

[0118] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention. [Explanation of symbols]

[0119] 1000,2000,3000,4000 Display optical system 1400, 2400, 3400, 4400 Panel section (display element) A Polarization-selective transflective element (first transflective surface) C Transmissive reflective film (second transmissive reflective surface) SP pupil plane

Claims

1. A display device having a display optical system provided for each of the right and left eyes, which guides display light from a display surface of a display element to a pupil plane, the display optical system includes a first transmissive-reflective surface and a second transmissive-reflective surface arranged in this order from a pupil plane side to a display surface side, the display device has an adjustment mechanism that changes at least one of a first distance between the first transmission-reflection surface and the second transmission-reflection surface and a second distance between the pupil plane and the display surface, The adjustment mechanism includes: A display device having an adjustment range that allows both convergence adjustment by changing the first distance and visibility adjustment by changing the first or second distance.

2. 2. The display device according to claim 1, wherein the adjustment mechanism includes an automatic adjustment mechanism that performs the convergence adjustment in accordance with an image displayed on the display surface, and a manual adjustment mechanism that performs the diopter adjustment.

3. 3. The display device according to claim 2, wherein the automatic adjustment mechanism and the manual adjustment mechanism are each capable of adjusting the diopter on the pupil plane from at least −4 diopters to 0 diopters.

4. 2. The display device according to claim 1, wherein the adjustment mechanism includes an automatic adjustment mechanism that performs the convergence adjustment and the visibility adjustment in accordance with an image displayed on the display surface.

5. 5. The display device according to claim 4, wherein the automatic adjustment mechanism is capable of adjusting the diopter on the pupil plane from at least −8 diopters to 0 diopters.

6. When the diopter on the pupil plane after adjustment by the adjustment mechanism is 0 diopter and when the diopter on the pupil plane is −8 diopter, the focal lengths of the display optical system including the diopter are ft[0D] and ft[−8D], respectively: 0.90≦ft[-8D] / ft[0D]≦1.10 6. The display device according to claim 3, wherein the following conditions are satisfied:

7. 2. The display device according to claim 1, wherein the adjustment mechanism drives the same transmissive-reflective surface of the first transmissive-reflective surface and the second transmissive-reflective surface for the convergence adjustment and the diopter adjustment.

8. 2. The display device according to claim 1, wherein the eye relief of the display optical system is 15 mm or less.

9. 2. The display device according to claim 1, wherein a diameter of a range through which the display light can pass on a surface of the display optical system facing the pupil plane is 50 mm or less.

10. 2. The display device according to claim 1, wherein a maximum half angle of view formed by a chief ray of the display light passing through the pupil plane is 30 degrees or more.

11. When the diopter on the pupil plane is 0 diopter after adjustment by the adjustment mechanism, the focal length of the display optical system including the diopter is ft[0D], and when the diopter on the pupil plane is 0 diopter, the focal length of the transmitted light path to the pupil plane on the pupil plane side of a first internal spacing, which is a spacing on the pupil plane side, that causes a change in the first spacing, is fe2[0D], 1.0≦fe2[0D] / ft[0D]≦10.0 2. The display device according to claim 1, wherein the following conditions are satisfied:

12. When the diopter on the pupil plane when adjustment is performed by the adjustment mechanism is 0 diopter, the focal length of the transmitted light path from the first transmitting-reflecting surface to the pupil plane on the pupil plane side is fe1[0D], 1.0≦fe1[0D] / fe2[0D]≦10.0 12. The display device according to claim 11, wherein the following condition is satisfied:

13. 2. The display device according to claim 1, wherein an exit angle of a chief ray of the display light passing through the pupil plane at a maximum half angle of view from the display surface is an angle directed away from the optical axis of the display optical system.

14. 6. The display device according to claim 2, wherein the automatic adjustment mechanism does not drive the display element, but drives two or less refractive elements made of resin.

15. 3. The display device according to claim 2, wherein the manual adjustment mechanism does not drive the display element.

16. 2. The display device according to claim 1, wherein the adjustment mechanism does not drive an optical element in the display optical system that has an optical surface facing the pupil plane.

17. When the diopter on the pupil plane is 0 diopter and −4 diopter, the change in the distance between the first transmissive-reflective surface and the second transmissive-reflective surface is dG, 0.5mm≦|dG|≦7.0mm 2. The display device according to claim 1, wherein the following conditions are satisfied:

18. When the diopter on the pupil plane after adjustment by the adjustment mechanism is 0 diopter, the focal length of the display optical system including the diopter is ft[0D], and when the diopter on the pupil plane is 0 diopter, the focal length upon reflection by the first transmissive-reflective surface is fr1[0D], -10.0≦fr1[0D] / ft[0D]≦-0.5 2. The display device according to claim 1, wherein the following conditions are satisfied:

19. 2. The display device according to claim 1, wherein the diagonal length of the square circumscribing the display surface is 1.3 inches or more.

20. 2. The display device according to claim 1, wherein the optical element driven by the automatic adjustment mechanism is composed of one or two refractive elements having an Abbe number based on the d-line of 50 or more, or two refractive elements having an Abbe number difference based on the d-line of 20 or more.

21. the display optical system includes an optical element that is not driven by the adjustment mechanism, 2. The display device according to claim 1, wherein the optical element has a diffractive surface.

22. 2. The display device according to claim 1, further comprising a plurality of refractive elements bonded together between the first and second transmission-reflection surfaces, the difference between the Abbe numbers of the elements relative to the d-line being 20 or more.

23. 2. The display device according to claim 1, wherein the display optical system guides the display light to the pupil plane via transmission at the second transmission-reflection surface, reflection at the first transmission-reflection surface, reflection at the second transmission-reflection surface, and transmission at the first transmission-reflection surface.

Images