display

Abstract

To provide an image observation device that can reduce ghost, while improving viewing angle characteristics at a peripheral viewing angle of an eyepiece optical system configured to fold an optical path.SOLUTION: A display is such that the center of a microlens corresponding to the luminescence center of a light-emitting device is deviated in a direction parallel to a plane, at a peripheral part of a display device. When the height of the microlens is defined as h, the height from a surface of an opening in the light-emitting device to the bottom face of the microlens as L, the amount of deviation of the center of the microlens from the center of the light-emitting device in the direction parallel to the plane at the peripheral part of the display device as ΔML, and an angle φ1=arctan(ΔML / (h+L)), 6.0°≤φ1≤37.5° is satisfied. When the height from the surface of the opening in the light-emitting device to an upper face of a color filter is defined as L2, the amount of deviation of the center of the color filter from the luminescence center of the light-emitting device in the direction parallel to the plane at the peripheral part of the display device as ΔCF, an angle φ2=arctan(ΔCF / L2), and the ratio A of the angle φ2 to the angle φ1 as A=φ2 / φ1, A satisfies 0≤A≤0.85.SELECTED DRAWING: Figure 4C

Description

[Technical Field]

[0001] The present invention relates to a display device that allows an image displayed on a display element to be viewed through an eyepiece optical system. [Background technology]

[0002] A head-mounted display (HMD) worn on the observer's head is known as an image observation device that allows an image displayed on a display element to be observed through an eyepiece optical system. In such HMDs, an eyepiece optical system that folds the optical path is sometimes used to achieve both compactness and a wide angle of view. Examples of such eyepiece optical systems include a polarizing optical system that uses polarized light and a free-form prism with a reflecting surface inside the lens.

[0003] In such eyepiece optical systems, the focal length is short, which increases the angle of light emitted from the display element at the peripheral field of view, making it easy for the viewing angle characteristics of the display element (brightness and chromaticity deviation) to deteriorate. Furthermore, ghost light, which is light that passes through an optical path unintended by the design, is easily generated. For example, when plastic lenses are used as part of a polarized optical system for the purpose of reducing weight, birefringence within the plastic lens can disrupt the polarization state of light, causing ghost light.

[0004] Patent Documents 1 and 2 disclose HMDs that have eyepiece optical systems with a wide angle of view that utilize polarized light. Patent Document 2 also discloses that the size of a color filter provided on a display element is increased from the center to the periphery, thereby improving the viewing angle characteristics at the peripheral angle of view. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-053152 [Patent Document 2] Special Publication No. 2019-61198 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the HMD disclosed in Patent Document 2, the light source and the center of the color filter are aligned, and the viewing angle characteristics in the normal direction of the display element are good, so ghosts caused by birefringence of the lens cannot be reduced.

[0007] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a display device that can reduce ghosting while improving the viewing angle characteristics at the peripheral angle of view of an eyepiece optical system configured to fold the optical path. [Means for solving the problem]

[0008] The display device according to the present invention includes a display element having a plurality of light-emitting elements arranged two-dimensionally on a plane, a plurality of microlenses provided corresponding to each of the plurality of light-emitting elements, and a color filter disposed between the light-emitting elements and the microlenses; an eyepiece optical system having at least one reflecting surface therein and directing light from the display surface of the display element to an exit pupil; In a display device, in a peripheral portion of the display element, a light emitting center of the light emitting element and a center of the microlens corresponding to the light emitting element are misaligned in a direction parallel to the plane, When the height of the microlens is h, the height from the surface of the opening of the light-emitting element to the bottom surface of the microlens is L, the amount of deviation between the center of the light-emitting element and the center of the microlens in the peripheral part of the display element in the direction parallel to the plane is ΔML, and the angle φ1 determined by the height h, the height L, and the amount of deviation ΔML is φ1=arctan(ΔML / (h+L)), then φ1 is 6.0°≦φ1≦37.5° Fulfilling When the height from the surface of the opening of the light-emitting element to the upper surface of the color filter is L2, the amount of deviation between the light-emitting center of the light-emitting element in the peripheral part of the display element and the center of the color filter in the direction parallel to the plane is ΔCF, the angle determined by the height L2 and the amount of deviation ΔCF is φ2=arctan(ΔCF / L2), and the ratio A of the angle φ1 to the angle φ2 is A=φ2 / φ1, A is 0≦A≦0.85 It is characterized in that the following is satisfied. [Effects of the Invention]

[0009] According to the present invention, it is possible to reduce ghosting while improving the field of view characteristics at the peripheral field angles of an eyepiece optical system configured to fold the optical path. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view of a display element according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of an edge of the display element of FIG. [Figure 3] FIG. 2 is a cross-sectional view of the display element according to the first embodiment. [Figure 4A] FIG. 10 is a cross-sectional view of a display element that does not have a microlens. [Figure 4B] FIG. 10 is a cross-sectional view of a display element in which the microlenses are not displaced. [Figure 4C] FIG. 2 is a cross-sectional view of the display element according to the first embodiment. [Figure 5A] 1 is a diagram showing the optical conditions for light rays that become normal light and ghost light. [Figure 5B] 1 is a diagram showing the optical conditions for light rays that become normal light and ghost light. [Figure 5C] 1 is a diagram showing the optical conditions for light rays that become normal light and ghost light. [Figure 6A] 10 is a diagram showing the relationship between a light ray that becomes normal light and a deviation amount ΔCF of a color filter. [Figure 6B] 10 is a diagram showing the relationship between a light ray that becomes normal light and a deviation amount ΔCF of a color filter. [Figure 7] FIG. 1 is a plan view of a display element according to a first embodiment. [Figure 8] FIG. 1 is a plan view of a display element according to a first embodiment. [Figure 9] FIG. 1 is a schematic diagram illustrating an example of a display device according to a first embodiment. [Figure 10] 1 is a diagram showing an imaging device and an electronic device according to a first embodiment. [Figure 11] FIG. 1 is a diagram showing an example of a display device according to a first embodiment. [Figure 12] 1 is a diagram showing an automobile and a lighting device according to a first embodiment. [Figure 13] FIG. 1 is a diagram showing an example of an eyeglass-type display device according to a first embodiment. [Figure 14] FIG. 1 is a diagram showing the configuration of an HMD according to a first embodiment. [Figure 15] FIG. 1 is an external view of an HMD according to a first embodiment. [Figure 16] FIG. 1 is a diagram showing the configuration of an eyepiece optical system according to a first embodiment. [Figure 17] FIG. 2 is a diagram showing the optical path of the eyepiece optical system according to the first embodiment. [Figure 18] FIG. 3 is a diagram showing the optical path of ghost light in the first embodiment. [Figure 19] FIG. 4 is a diagram showing the viewing angle characteristics at the horizontal end of the display surface in the first embodiment. [Figure 20] FIG. 10 is a diagram showing the configuration of an HMD according to a second embodiment. [Figure 21] FIG. 10 is a diagram showing the configuration of an eyepiece optical system according to a second embodiment. [Figure 22] FIG. 10 is a diagram showing the optical path of the eyepiece optical system according to the second embodiment. [Figure 23] FIG. 10 is a diagram showing the optical path of ghost light in the second embodiment. [Figure 24] FIG. 10 is a diagram showing the configuration of an HMD according to a third embodiment. [Figure 25] FIG. 10 is a diagram showing the configuration of an eyepiece optical system according to a third embodiment. [Figure 26] FIG. 11 is a diagram showing the optical path of an eyepiece optical system according to a third embodiment. [Figure 27] FIG. 11 is a diagram showing the optical path of ghost light in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] In an embodiment of the present invention, by shifting the center position of a microlens provided on a light-emitting element from the center position of the light-emitting element, it is possible to reduce ghosts while improving the field of view characteristics at the peripheral field angle of an eyepiece optical system that folds the optical path.

[0013] First, we will explain the configuration of a display element that improves viewing angle characteristics and reduces ghosting. Next, as examples of combinations of a display element and an eyepiece optical system that folds the optical path, we will show embodiments 1 and 2 that use a polarized optical system, and embodiment 3 that uses a free-form surface prism. Desirable configurations of eyepiece optical systems that fold the optical path will be explained in the embodiments.

[0014] Hereinafter, display elements according to embodiments of the present invention will be described with reference to the drawings. Note that, for parts not specifically shown or described in this specification, well-known or publicly known techniques in the relevant technical field are applied. Furthermore, the present invention is not limited to the embodiments described below.

[0015] (Embodiment 1) FIG. 1 is a plan view of a display element according to a first embodiment of the present invention. The display element 100 has a display area 1 in which light-emitting elements 10 are arranged two-dimensionally on the main surface (plane) of a substrate 8 (see FIG. 3), and which generates an image. However, the effects of the present invention do not depend on the pixel arrangement. In other words, the arrangement may be a delta arrangement as exemplified in FIG. 1, a stripe arrangement, or a square arrangement.

[0016] Fig. 2 is an enlarged view of edge region 2 of display region 1 shown in Fig. 1. As shown in Fig. 2, edge region 2 (display region 1) is provided with light-emitting elements 10 arranged on the main surface of substrate 8 and microlenses 15 into which light from light-emitting regions 17 (see Fig. 3) of light-emitting elements 10 is incident. In a plan view from a direction perpendicular to the main surface of substrate 8, the centers of light-emitting regions 17 of light-emitting elements 10 and the centers of microlenses 15 are offset in a direction parallel to the main surface. Edge region 2 is sometimes called a peripheral region because it is located on the periphery of the center of the display region.

[0017] 3(a) is a cross-sectional view of the edge region 2 taken along line A-A' in FIG. 2, showing a light-emitting element having a convex microlens on the side opposite to the substrate. Here, an example is shown in which organic EL elements are used as the light-emitting elements 10. In the figure, the organic EL elements (light-emitting elements 10) are arranged at intervals of a pitch D. The pitch D is the distance in the main surface direction of the substrate 8 between the center position 18 of the light-emitting region 17 of one light-emitting element 10 and the center position 18' of the light-emitting region 17 of an adjacent light-emitting element 10.

[0018] The light-emitting elements 10 on the substrate 8 have a first electrode 11 disposed on the main surface of the substrate 8, an organic layer 12 including a light-emitting layer, and a second electrode 13 disposed on the first electrode 11 with the organic layer 12 sandwiched between them. In order to maintain the characteristics of the light-emitting elements 10 at the outermost periphery of the display region 1, dummy pixels 10' are disposed outside the range indicated by line A-A', which is the edge of the display region 1. The dummy pixels 10' may be formed in multiple columns and rows.

[0019] The organic layer 12 may be configured such that a light-emitting layer that emits a single emission color is formed as a common layer between the light-emitting elements 10 so that the display element 100 can display a single emission color. Further, the organic layer 12 may be configured by patterning light-emitting layers that emit different colors for each light-emitting element 10 so that the display element 100 can display at least two or more colors. Each pixel of the display element 100 has an insulating layer 16 that covers the end portion of the first electrode 11 and has an opening on the first electrode 11, a protective layer 14 disposed on the second electrode 13, and a microlens 15. Light emitted from the light-emitting element 10 is incident on the microlens 15.

[0020] In the present embodiment, the microlens 15 is disposed so as to be shifted in the direction indicated by arrow B with respect to the light-emitting region 17 of the light-emitting element 10. The direction indicated by arrow B is the direction in which the principal ray of the direct-vision optical system that folds the optical path is projected onto the principal plane when the display element 100 is viewed in plan view. With such a configuration, the emission intensity reaching the observer's pupil through the direct-vision optical system is increased and the utilization efficiency of the light emitted from the light-emitting layer is improved as compared with the case where no microlens is provided or the case where the microlens and the light-emitting region are arranged to overlap in plan view. In addition, the emission intensity of light that passes through an unintended optical path and is perceived by the observer as a ghost is reduced. Details of the effects will be described later. Further, in the present embodiment shown in FIG. 3(a), it is desirable that the refractive index n1 of the microlens and the refractive index n0 of the medium above the microlens satisfy the relationship n0 < n1. Note that the light-emitting region 17 of the light-emitting element 10 refers to a portion where the first electrode 11, the organic layer 12, and the second electrode 13 are laminated at the opening of the insulating layer 16.

[0021] The misalignment between the microlens 15 and the light-emitting region 17 in each light-emitting element 10 means that the center position 19 of the microlens 15 and the center position 18 of the light-emitting region 17 do not overlap in a planar view, but are separated by a certain distance. The center of the microlens 15 is the center of gravity of the shape (external shape) formed by the lines connecting the end portions in a planar view. The end portion of the microlens 15 is the position where the height in the Z direction is lowest in the cross-sectional view of the microlens 15. In FIG. 3(a), the cross-section of the microlens 15 is spherical (a partially missing sphere and a hemisphere are also included in the spherical shape), and in this case, the center of the microlens 15 coincides with the vertex of the microlens 15.

[0022] In this embodiment, the microlens 15 is disposed so as to be offset from the light-emitting region 17 of the light-emitting element 10. That is, in a plan view of the surface of the substrate 8 on which the light-emitting element 10 is disposed, the center 19 of the microlens 15 and the center position 18 of the light-emitting region 17 are separated by a certain distance (do not coincide). In addition, because the cross-sectional shape of the microlens 15 is spherical in this case, the vertex of the microlens 15 and the center of the light-emitting region 17 are also separated by a certain distance.

[0023] In this embodiment, the pitch of the microlenses 15 (the distance between the centers of adjacent microlenses in a plan view of the surface of the substrate 8 on which the light emitting elements 10 are arranged) is constant. In addition, the pitch of the light emitting elements 10 (the distance between the centers of the light emitting regions of adjacent light emitting elements 10 in a plan view of the surface of the substrate 8 on which the light emitting elements 10 are arranged) is also constant and matches the pitch of the microlenses 15. Therefore, the microlenses 15 and the light emitting regions 17 are arranged with a constant distance (shift amount). That is, this embodiment shows an example in which the distance between the center of the microlens 15 and the center of the light emitting region 17 in a plan view (microlens shift amount) is constant for each pixel.

[0024] When the organic layer 12 is composed of layers that emit white light, as shown in Fig. 3(b), a color filter 20 may be provided between the light-emitting element 10 and the microlens 15. Fig. 3(b) shows an example in which the color filter 20 is arranged so as to be displaced with respect to the light-emitting region 17. That is, in a plan view of the surface of the substrate 8 on which the light-emitting element 10 is arranged, the center 21 of the color filter 20 and the center 18 of the light-emitting region 17 are separated by a certain distance. However, in order to suppress color shift, the color filter 20 may be arranged so as not to be displaced with respect to the light-emitting region 17. That is, in a plan view of the surface of the substrate 8 on which the light-emitting element 10 is arranged, the center 21 of the color filter 20 and the center position 18 of the light-emitting region 17 may be arranged to coincide with each other.

[0025] Fig. 3(c) is a cross-sectional schematic view of a light-emitting device in which the forms of the color filter and the microlens are different. The microlens 15' has a convex shape in the downward direction of the paper surface, which is different from other embodiments. The downward direction of the paper surface can also be said to be the direction from the semi-transmissive electrode to the reflective electrode. Between the microlens 15' and the protective layer 14, there may be a void or other substances may be filled. However, it is desirable that the refractive index n1 of the microlens and the refractive index n2 of the medium below the microlens satisfy the relationship n2 < n1. Further, in Fig. 3(c), the color filter 20 is arranged above the microlens 15', but it may also be arranged between the microlens 15' and the protective layer 14. Note that the center of the microlens 15' is the centroid of the shape (outer shape) formed by the line connecting the ends in a plan view. The end of the microlens 15' is the position where the height in the Z direction is the lowest in the cross-sectional view of the microlens 15. In Fig. 3(c), the cross-section of the microlens 15' is a spherical shape (including a partially missing spherical surface and a hemisphere is also included in the spherical shape). In this case, the center of the microlens 15' coincides with the vertex of the microlens 15'.

[0026] The substrate 8 may be made of any material that can support the first electrode 11, the organic layer 12, and the second electrode 13. For example, glass, plastic, silicon, etc. can be used. Switching elements such as transistors, wirings, and interlayer insulating films (not shown) may be arranged on the substrate 8.

[0027] The first electrode 11 may be transparent or opaque. If it is opaque, a metal material with a reflectance of 70% or more at the emission wavelength is desirable. Metals such as Al and Ag, alloys of these with Si, Cu, Ni, Nd, etc., or ITO, IZO, AZO, and IGZO can be used. Note that the emission wavelength here refers to the spectral range of light emitted from the organic layer 12. The first electrode 11 may be a laminated electrode with a barrier electrode made of a metal such as Ti, W, Mo, or Au or an alloy thereof, as long as the reflectance is higher than the desired value, or may be a laminated electrode with a transparent oxide film electrode such as ITO or IZO.

[0028] On the other hand, when the first electrode 11 is a transparent electrode, a reflective layer may be further provided below the first electrode 11. For example, ITO, IZO, AZO, IGZO, etc. may be used as the transparent electrode. In order to optimize the optical path, an insulating film may be further provided between the reflective layer and the transparent electrode.

[0029] The second electrode 13 is disposed on the organic layer 12 and has light-transmitting properties. The second electrode 13 may be made of a semi-transparent material that transmits part of the light that reaches its surface and reflects the other part (i.e., semi-transparent and reflective). Examples of the material for the second electrode 13 include transparent materials such as transparent conductive oxides. Semi-transparent materials may also be used, such as elemental metals such as aluminum, silver, and gold, alkali metals such as lithium and cesium, alkaline earth metals such as magnesium, calcium, and barium, and alloys containing these metals. As semi-transparent materials, alloys primarily containing magnesium or silver are particularly preferred. The second electrode 13 may have a laminated structure of layers containing the above materials, as long as it has a desirable transmittance. The second electrode 13 may also be shared by multiple light-emitting elements 10.

[0030] Either the first electrode 11 or the second electrode 13 functions as an anode, and the other functions as a cathode. That is, the first electrode 11 may be an anode and the second electrode 13 may be a cathode, or vice versa. The organic layer 12 is disposed on the first electrode 11 and can be formed by a known technique such as vapor deposition or spin coating.

[0031] The organic layer 12 may be composed of multiple layers. When the organic layer 12 is an organic compound layer, the multiple layers may include any one or combination of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0032] The light-emitting layer emits light by recombining holes injected from the anode and electrons injected from the cathode in the organic compound layer. The light-emitting layer may be a single layer or multiple layers. Any of the light-emitting layers may contain a red light-emitting material, a green light-emitting material, and a red light-emitting material. White light can be obtained by mixing the emitted colors. Any of the light-emitting layers may contain light-emitting materials of complementary colors, such as a blue light-emitting material and a yellow light-emitting material. The light-emitting material may be a fluorescent material, a phosphorescent material, a delayed fluorescent material, or a quantum dot such as CdS or perovskite. Different colors may be emitted by changing the material or composition of the light-emitting layer for each pixel. Each light-emitting element 10 may have its own light-emitting layer. In this case, the light-emitting layer may be patterned for each light-emitting element 10.

[0033] The protective layer 14 is an insulating layer, and preferably contains an inorganic material that is translucent and has low permeability to oxygen and moisture from the outside. For example, the protective layer 14 can be made using inorganic materials such as silicon nitride (SiN), silicon oxynitride (SiON), silicon oxide (SiOx), aluminum oxide (Al2O3), and titanium oxide (TiO2). In particular, inorganic materials such as SiN, SiON, and Al2O3 are preferred in terms of protective performance. The protective layer 14 is preferably formed by chemical vapor deposition (CVD), atomic layer deposition (ALD), or sputtering.

[0034] The protective layer 14 may have a single layer structure or a laminated structure combining the above materials and forming methods, as long as it has sufficient moisture-blocking properties. For example, it may be a laminate of a silicon nitride layer and a high-density layer formed by atomic deposition. Furthermore, the protective layer 14 may have an organic layer as long as it maintains moisture-blocking properties. Examples of organic layers include polyacrylate, polyimide, polyester, and epoxy. Furthermore, the protective layer 14 may be disposed across multiple light-emitting elements 10. A planarizing layer may be formed between the protective layer 14 and the microlenses 15 to smooth out any irregularities on the protective layer 14. A color filter may be disposed between the microlenses 15 and the protective layer 14 or between the microlenses 15 and the planarizing layer.

[0035] The microlenses 15 can be formed by an exposure and development process. Specifically, a film (photoresist film) is formed from a material for forming the microlenses, and the photoresist film is exposed and developed using a mask with a continuous gradation change. Such a mask can be a gray mask or an area gradation mask that allows continuous gradation light irradiation on the imaging surface by changing the density distribution of dots made of a light-shielding film below the resolution of the exposure device.

[0036] Furthermore, the lens shape can be adjusted by etching back the microlenses formed by the exposure and development process. The shape of the microlenses may be spherical or may have an asymmetric cross section, as long as it can refract the emitted light.

[0037] Next, the effects of this embodiment will be described using an example of a light-emitting device having a microlens that is convex on the side opposite to the substrate. The effects of this embodiment do not depend on the direction of the convex shape of the microlens. In other words, a microlens that is convex downward in the plane of the page, as shown in FIG. 3(c), may also be used.

[0038] Figures 4A to 4C are cross-sectional views of the edge region 2 taken along line A-A' in Figure 2. Figures 4A and 4B respectively show a configuration in which no microlenses 15 are arranged, and a configuration in which the microlenses 15 and the light-emitting region 17 are arranged so as to overlap each other without any misalignment in plan view.

[0039] In Figure 4A, radiation angle 21 represents the radiation angle in air of the chief ray of normal light, and radiation angle 22 represents the radiation angle in air of ghost light. Normal light is light that passes through the optical path designed by the lens and forms an image at the observer's pupil. The chief ray is the normal light that passes through the center of the observer's pupil. In an eyepiece optical system that folds the optical path, the focal length is shortened, so the radiation angle in air of the chief ray of normal light becomes larger at the edges of the display area 1, as shown in Figure 4A.

[0040] On the other hand, ghost light is light emitted from a light-emitting element, travels an optical path unintended by the design, and is observed as a ghost by the viewer. Generally, the optical path of ghost light is determined by the relative positions of the light-emitting elements in the display area 1 and the viewer's pupil, as shown in Figures 18 and 23. In this case, as shown in Figure 4A, the radiation angle becomes small and its direction is opposite to that of normal light with respect to the normal direction to the main surface of the substrate.

[0041] FIG. 4A shows light emitted from the light-emitting element 10 without a microlens. The direction of the vector (arrow) represents the direction of light propagation, and the magnitude of the vector represents the intensity of the emitted light. Generally, light-emitting elements have radiation angle dependence, with the radiation intensity decreasing as the radiation angle increases. Therefore, without a microlens, light 23 emitted in the direction of radiation angle 21 of the chief ray of normal light is weaker than radiation light 24 emitted in the direction of radiation angle 22 of the ghost light. In other words, at the edge of the display area 1, the intensity of the light emitted from the light-emitting element is stronger for ghost light than for normal light. Similarly, when the microlens 15 and the light-emitting area 17 are arranged so as to overlap in a planar view as shown in FIG. 4B, light 25 emitted in the direction of radiation angle 21 of the chief ray of normal light is weaker than radiation light 26 emitted in the direction of radiation angle 22 of the ghost light.

[0042] FIG. 4C shows the case of this embodiment, where the microlens 15 and the light-emitting region 17 are offset by a certain distance. By offsetting the microlens 15 in the direction indicated by arrow B relative to the light-emitting region 17, light is refracted through surface 28 of the microlens 15, dramatically increasing the intensity of light 27 emitted in the direction of radiation angle 21 of the chief ray of normal light. At the same time, the intensity of light emitted in the direction of radiation angle 22 of ghost light is significantly reduced. This is because the ghost light is refracted toward wider angles mainly at surface 29 of the adjacent microlens 15 or is trapped within the microlens by total internal reflection. Here, surfaces 28 and 29 refer to the surfaces facing in the opposite direction and the forward direction, respectively, relative to the plane that passes through the center of the microlens 15 and is perpendicular to the direction of arrow B, as shown in the upper right diagram of FIG. 4C, which is a plan view of the microlens 15 in FIG. 4C.

[0043] In this way, by arranging the microlens 15 and the light-emitting area 17 at a certain distance from each other, it is possible not only to increase the light emission intensity of normal light at the edge of the display area 1, but also to reduce ghost light.

[0044] 5A is a cross-sectional view showing the relationship between light emitting region 17, microlens 15, and the emission angle of normal light. In FIGS. 5A to 5C, microlenses 15 having height h, radius r, and refractive index n are arranged.

[0045] Light is emitted from light-emitting region 17 at an angle θ1 and is bent in the direction of angle θ2 by point A of microlens 15. The inclination of the normal to the microlens surface at point A relative to the normal to substrate 8 at this time is defined as angle α. If α + θ1 is defined as β, then the following equation (1) holds according to Snell's law.

[0046] 1×sin(θ2+α)=n×sinβ=n×sin(θ1+α) …(1) When equation (1) is solved for θ1, θ1 is expressed by equation (2).

[0047] θ1=sin -1 {sin(θ2+α) / n}-α …(2) As shown in Figure 5A, when it is desired to emit light from the light-emitting region 17 to the wide-angle side (when it is desired to make θ2 > θ1), the region where α is positive, i.e., the region to the right of the vertex of the microlens 15 in Figure 5A, i.e., the light incident on surface 28, is mainly used.

[0048] In order to effectively utilize the microlens 15 up to its edge, it is desirable that α<θ2 be satisfied over the entire area of ​​the microlens 15, where θ2 is the radiation angle of the chief ray of normal light.

[0049] Here, ΔML is the amount of deviation of the vertex of microlens 15 from the center of light-emitting area 17. To increase the emission intensity at a desired emission angle θ2, θ1 and β that satisfy equation (2) above are calculated for α at each point on microlens 15, and ΔML is set so that light-emitting area X is located in the direction of one of the angles β. In other words, the greater the ratio of light-emitting area X to light-emitting area 17 shown in FIG. 5A, the greater the light intensity of the normal light.

[0050] On the other hand, Figure 5B is a cross-sectional view showing the relationship between the light-emitting area 17, microlens 15, and the emission angle of ghost light. Light is emitted from the light-emitting area at angles θ1' and θ1", and is bent in the direction of angle θ2' at points A' and A" of the microlens, respectively. The inclinations of the normal to the microlens surface at points A and A" with respect to the normal to substrate 8 at this time are angles α' and α", respectively. As in the case of normal light, θ1' and θ1" are expressed by equations (3) and (4).

[0051] θ'1=sin -1 {sin(θ2'+α') / n}-α' …(3) θ”1=sin -1 {sin(θ2'+α”) / n}-α” …(4) To weaken the emission intensity of ghost light with an emission angle θ2', it is desirable that light-emitting areas Y1 and Y2 do not overlap with light-emitting area 17. Specifically, θ1' and θ1" calculated from equations (3) and (4) should be increased. This is because increasing θ1' and θ1" reduces the intensity of light emitted from the light-emitting element. Furthermore, if the angle exceeds a certain critical angle, total reflection occurs internally and the light does not reach the microlens.

[0052] In this way, the shift amount ΔML can be determined so that the light-emitting area X that emits normal light is large relative to the light-emitting area 17, and the light-emitting areas Y1 and Y2 that emit in the direction that becomes ghost light are small. In this embodiment, the aperture shape can be optimized as appropriate, and the shape may be circular, hexagonal, elliptical, or the like. For example, the aperture shape of the pixel may be formed so that X is large and Y1 and Y2 are small.

[0053] As shown in Figure 5C, it is desirable that the range of the shift amount ΔML at the edge 2 of the display area 1 (see Figure 1) satisfies equation (5), where h is the height of the microlens 15, L is the height from the first electrode 11 to the bottom surface of the microlens 15, and φ1 = arctan(ΔML / (h + L)) [degrees] is the inclination angle of the line connecting the center position 19 of the microlens 15 and the center position 18 of the light-emitting area 17 with respect to the normal direction of the substrate 8.

[0054] 6.0° ≦φ1≦37.5° …(5) Next, the displacement amount ΔCF of the color filter will be described. When the organic layer 12 is composed of a layer that emits white light, a color filter 20 may be provided between the light-emitting element 10 and the microlens 15, as shown in FIG. 3(b). The range of ΔCF at the edge 2 of the display region 1 desirably satisfies formula (6), where L2 is the height from the first electrode 11 to the upper surface of the color filter 20, φ2 = arctan(ΔCF / L2) [degrees] is the inclination angle of the line connecting the center position 21 of the upper surface of the color filter 20 and the center position 18 of the light-emitting region 17 with respect to the normal direction of the substrate 8, and A = φ2 / φ1 is the ratio A of φ1 to φ2.

[0055] 0 ≦ A ≦ 0.85 … (6) 6A and 6B are cross-sectional views showing the positional relationship between the light-emitting region 17 and the microlens 15 at the edge 2 of the display region 1, illustrating the component of normal light emitted in the direction of the radiation angle 21. FIG. 6A illustrates the case where A=1, which is an example where formula (6) is not satisfied. As described in FIG. 5A, the light emitted in the direction of the normal radiation angle 21 is mainly radiation light 32 transmitted through the surface 28 of the microlens 15, but some radiation light 33 also exists that has passed through the surface 29. The emission intensity of radiation light 33 is lower than that of radiation light 32 because the radiation angle from the normal direction of the substrate 8 is larger. However, because the radiation angle is larger, the degree of color shift of radiation light 33 is larger than that of radiation light 32. Therefore, if the color filter 20 is shifted by the same amount (A=1) as the microlens 15, as shown in FIG. 6A, the color shift due to radiation light 33 will be large. Here, the color shift is the difference between the chromaticity in the normal direction of the substrate 8 at the center of the display area 1 and the chromaticity of the light emitted from the edge 2 of the display area 1 in the direction of the radiation angle 21 .

[0056] 6B is a cross-sectional view showing the positional relationship between the light-emitting region 17 and the microlens 15 at the edge 2 of the display region 1 when formula (6) is satisfied. As can be seen from FIG. 6B, by reducing the shift amount ΔCF, the color filter can block the emitted light 33, which has a large color shift, and therefore the color shift can be easily suppressed. As will be described in detail later, by appropriately optimizing the shift amounts ΔML and ΔCF, it is possible to suppress the color shift while suppressing the emission intensity of ghost light.

[0057] However, when a color filter is placed on top of a microlens that is convex downward in the plane of the page as shown in Fig. 3(c), it is not necessary to satisfy the relational expression (6), and A may be set to 1. This is because the emitted light 33 emitted to the wide-angle side shown in Fig. 6B is totally reflected by the low-refractive-index medium between the protective layer and the microlens, and does not reach the microlens.

[0058] In this embodiment, the deviation amount ΔML is adjusted appropriately for each position within the display area 1 in accordance with the design of the eyepiece optical system. FIG. 7 is a cross-sectional view showing the positional relationship between the microlenses 15 and the light-emitting area 17 when the display area 1 is cut along line E-E'. Here, as in the previous examples, an example of a light-emitting element having a microlens that is convex on the side opposite the substrate will be described. The effect of this embodiment does not depend on the direction of the convex shape of the microlens. In other words, a microlens that is convex downward in the plane of the page, as shown in FIG. 3(c), may also be used.

[0059] As shown in FIG. 7, the microlenses 15 may be arranged so that the shift amount ΔML(34) at the center position of the display area 1 is 0, and the shift amount ΔML increases toward the edge of the display area 1, such as ΔML(35), ΔML(36), and ΔML(37). As shown in FIGS. 18 and 23, the amount of ghost light is primarily determined by the linear relationship between the position of the light-emitting element 17 in the display area 1 and the viewer's pupil. Therefore, the shift amounts ΔML(34) to ΔML(37) may be linearly increased as a function of the position of the light-emitting element 17. Furthermore, the shift amount ΔML may be formed so as to change continuously macroscopically with respect to the position of the light-emitting element 17. As long as it is continuous macroscopically, the shift amount may be changed for each pixel, or may be changed in a stepped manner within a certain range. It is also possible to change a certain range pixel by pixel, and then change the remaining range in a stepped manner. However, if the focal length is made shorter, the change in the aspherical shape of the lens surface closer to the display element 100 will be greater, and the rate of change of the radiation angle of the ghost light may increase as it approaches the edge of the display area 1. In this case, the rate of change of the deviation amount ΔML may be increased in accordance with the rate of change of the radiation angle of the ghost light. Also, while FIG. 7 shows a case where the deviation amount ΔML (34) at the center of the display area 1 is 0, it does not necessarily have to be 0. Also, the deviation amount ΔML may be kept constant throughout the display area 1.

[0060] In an image observation device having an eyepiece optical system, when the deviation amount ΔML increases toward the ends of the display area 1 as shown in Fig. 7, the value of the deviation amount ΔML is designed so that the viewing angle characteristics at the horizontal end 38 or the upper and lower ends 39 in Fig. 8 are optimal. In this case, in the diagonal areas 40, 41, 42, and 43 in Fig. 8(a), the deviation amount ΔML may become close to the pitch D of the light-emitting elements, which may increase the emission intensity of ghost light. In such a case, it is not necessary to arrange light-emitting elements in at least one of the diagonal areas 40, 41, 42, and 43 of the display area 1 as shown in Fig. 8(a).

[0061] If light-emitting elements are not arranged in all diagonal regions, the display region will be an octagon (n-gon) like region 44. Furthermore, if light-emitting elements are not arranged only in diagonal regions 40 and 42, the display region will be a hexagon consisting of regions 41, 43, and 44. As in FIG. 8(a), it is not necessary to arrange one or both of light-emitting elements and microlenses in at least one of diagonal regions 45, 46, 47, and 48 in FIG. 8(b). In other words, if light-emitting elements are not arranged in all diagonal regions, the display region will be a hexagon like region 49. Microlenses may or may not be arranged in regions where light-emitting elements are not arranged. The arrangement of light-emitting elements and microlenses in this embodiment can be adjusted appropriately by optical design, and a configuration in which light-emitting elements are arranged in diagonal regions and only microlenses are not arranged may be used.

[0062] Alternatively, the microlens misalignment amount ΔML in the diagonal regions 40, 41, 42, 43 (or 45, 46, 47, 48) may be made constant and matched with the misalignment amount at the end 38 or end 39 so that it is not larger than the microlens misalignment amount ΔML at the horizontal end 38 and the upper and lower end 39.

[0063] As explained above, by shifting the light-emitting area 17 and the microlens 15 in a direction parallel to the main surface of the substrate 8 at the end of the display area 1, the light emission intensity of the normal light of the eyepiece optical system that folds the optical path can be increased, thereby reducing ghosts.

[0064] Next, several embodiments will be used to explain how the above-mentioned display element is effective in various eyepiece optical systems that fold optical paths. In embodiments 1 and 2, examples in which the display element is applied to a polarized optical system that uses polarized light are shown. In embodiment 3, an example in which the display element is applied to a free-form prism is shown. In addition, each embodiment will also explain desirable forms of eyepiece optical systems that fold optical paths. The embodiments described here are merely representative examples, and various modifications and changes to each embodiment are possible when practicing the present invention.

[0065] Here, the configuration of the display device according to this embodiment will be described.

[0066] 9 is a schematic diagram illustrating an example of a display device according to this embodiment. The display device 1000 may include, between an upper cover 1001 and a lower cover 1009, a touch panel 1003, a display panel 1005 including a display element 100, a frame 1006, a circuit board 1007, and a battery 1008. The touch panel 1003 and the display panel 1005 are connected by flexible printed circuits FPCs 1002 and 1004. Transistors are printed on the circuit board 1007. The battery 1008 may not be provided if the display device is not a portable device, and may be provided in a different position even if the display device is a portable device.

[0067] The display device according to this embodiment may have color filters having red, green, and blue colors, which may be arranged in a delta arrangement.

[0068] The display device according to the present embodiment may be used as a display unit of a mobile terminal. In this case, the display device may have both a display function and an operation function. Examples of the mobile terminal include a mobile phone such as a smartphone, a tablet, and a head-mounted display.

[0069] The display device according to this embodiment may be used as a display unit of an imaging device having an optical unit with a plurality of lenses and an imaging element that receives light that has passed through the optical unit. The imaging device may have a display unit that displays information acquired by the imaging element. The display unit may be a display unit exposed to the outside of the imaging device or a display unit disposed within a viewfinder. The imaging device may be a digital camera or a digital video camera.

[0070] 10(a) is a schematic diagram showing an example of an imaging device according to this embodiment. The imaging device 1100 may have a viewfinder 1101, a rear display 1102, an operation unit 1103, and a housing 1104. The viewfinder 1101 may have a display device according to this embodiment. In this case, the display device may display not only an image to be captured, but also environmental information, imaging instructions, and the like. The environmental information may include the intensity of external light, the direction of external light, the speed at which the subject is moving, the possibility that the subject will be blocked by an obstruction, and the like.

[0071] Since the optimum timing for capturing an image is very short, it is better to display information as soon as possible. Therefore, it is preferable to use a display device using the organic light-emitting element of the present invention. This is because the organic light-emitting element has a fast response speed. A display device using an organic light-emitting element can be used more preferably than a liquid crystal display device, which requires a high display speed.

[0072] The imaging device 1100 has an optical section (not shown). The optical section has multiple lenses, which form an image on an imaging element housed in a housing 1104. The focus of the multiple lenses can be adjusted by adjusting their relative positions. This operation can also be performed automatically. The imaging device may also be called a photoelectric conversion device. Instead of sequentially capturing images, the photoelectric conversion device can include an imaging method that detects the difference from the previous image, or a method of cutting out an image from a constantly recorded image, etc.

[0073] FIG. 10(b) is a schematic diagram showing an example of an electronic device according to this embodiment. The electronic device 1200 has a display unit 1201, an operation unit 1202, and a housing 1203. The housing 1203 may have a circuit, a printed circuit board having the circuit, a battery, and a communication unit. The operation unit 1202 may be a button or a touch panel type reaction unit. The operation unit may be a biometric recognition unit that recognizes a fingerprint to unlock the device, etc. An electronic device having a communication unit can also be called a communication device. The electronic device may further have a camera function by including a lens and an image sensor. An image captured by the camera function is displayed on the display unit. Examples of the electronic device include a smartphone and a laptop computer.

[0074] 11A and 11B are schematic diagrams illustrating an example of a display device according to this embodiment. Fig. 11A shows a display device such as a television monitor or a PC monitor. The display device 1300 has a frame 1301 and a display unit 1302. The light-emitting device according to this embodiment may be used in the display unit 1302.

[0075] It has a frame 1301 and a base 1303 that supports a display unit 1302. The base 1303 is not limited to the form shown in Fig. 11(a). The bottom side of the frame 1301 may also serve as the base.

[0076] The frame 1301 and the display unit 1302 may be curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

[0077] FIG. 11(b) is a schematic diagram illustrating another example of a display device according to this embodiment. The display device 1310 in FIG. 11(b) has a foldable display surface. The display device 1310 has a first display unit 1311, a second display unit 1312, a housing 1313, and a bending point 1314. The first display unit 1311 and the second display unit 1312 may include a light-emitting device according to this embodiment. The first display unit 1311 and the second display unit 1312 may be a single, seamless display unit. The first display unit 1311 and the second display unit 1312 can be separated by the bending point. The first display unit 1311 and the second display unit 1312 may display different images, or the first and second display units may display a single image.

[0078] FIG. 12(a) is a schematic diagram illustrating an example of an illumination device according to this embodiment. The illumination device 1400 may include a housing 1401, a light source 1402 including a display element 100, a circuit board 1403, an optical film 1404, and a light diffusion unit 1405. The light source may include an organic light-emitting element according to this embodiment. The optical filter may be a filter that improves the color rendering of the light source. The light diffusion unit can effectively diffuse light from the light source, such as for illumination, and deliver the light over a wide area. The optical filter and the light diffusion unit may be provided on the light emission side of the illumination device. If necessary, a cover may be provided on the outermost part.

[0079] The lighting device is, for example, a device for illuminating a room. The lighting device may emit white, daylight white, or any other color from blue to red. It may have a dimming circuit for dimming these colors. The lighting device may have the organic light-emitting element of the present invention and a power supply circuit connected thereto. The power supply circuit is a circuit for converting AC voltage to DC voltage. Furthermore, white has a color temperature of 4200K, and daylight white has a color temperature of 5000K. The lighting device may have a color filter.

[0080] The lighting device according to this embodiment may also include a heat dissipation unit, which dissipates heat from within the device to the outside, and may be made of a material such as a metal with a high specific heat capacity or liquid silicon.

[0081] 12(b) is a schematic diagram of an automobile, which is an example of a moving body according to this embodiment. The automobile has tail lamps, which are an example of lighting fixtures. The automobile 1500 has tail lamps 1501, and may be configured to turn on the tail lamps when braking or the like is performed.

[0082] A tail lamp 1501 may include an organic light-emitting element according to this embodiment. The tail lamp may include a protective member for protecting the organic EL element. The protective member may be made of any material as long as it has a certain degree of strength and is transparent, but it is preferably made of polycarbonate or the like. Polycarbonate may be mixed with a furandicarboxylic acid derivative, an acrylonitrile derivative, or the like.

[0083] An automobile 1500 may have a body 1503 and a window 1502 attached thereto. The window may be a transparent display as long as it is not a window for checking the front and rear of the automobile. The transparent display may have an organic light-emitting element according to this embodiment. In this case, constituent materials of the electrodes and the like of the organic light-emitting element are made of transparent materials.

[0084] The moving body according to this embodiment may be a ship, an aircraft, a drone, or the like. The moving body may have a body and a lighting device provided on the body. The lighting device may emit light to indicate the position of the body. The lighting device has the organic light-emitting element according to this embodiment.

[0085] 13 is a schematic diagram of an eyeglass-type display device, which is an example of a wearable device to which a light-emitting device according to an embodiment of the present invention is applied. The display device can be applied to systems that can be worn as a wearable device, such as smart glasses, HMDs, and smart contact lenses. An image capturing and displaying device used in such an application example may include an image capturing device capable of photoelectrically converting visible light and a displaying device capable of emitting visible light.

[0086] 13(a) illustrates glasses 1600 (smart glasses) according to one application example. An imaging device 1602 such as a CMOS sensor or SPAD is provided on the front side of a lens 1601 of the glasses 1600. Furthermore, a display device according to any of the above-described embodiments is provided on the back side of the lens 1601.

[0087] The glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the image capture device 1602 and the display device according to each embodiment. The control device 1603 also controls the operations of the image capture device 1602 and the display device. The lens 1601 is formed with an optical system for focusing light onto the image capture device 1602.

[0088] FIG. 13(b) illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 include a control device 1612, which is equipped with an imaging device equivalent to the imaging device 1602 and a display device. A lens 1611 includes an optical system for projecting light emitted from the imaging device and the display device within the control device 1612, and an image is projected onto the lens 1611. The control device 1612 functions as a power source for supplying power to the imaging device and the display device and controls the operation of the imaging device and the display device. The control device may also include a gaze detection unit for detecting the wearer's gaze. Infrared light may be used for gaze detection. The infrared light emitter emits infrared light toward the eyeball of a user gazing at a displayed image. An imaging unit with a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an image of the eyeball. A reduction unit for reducing light from the infrared light emitter to the display unit in a planar view reduces degradation of image quality.

[0089] The gaze of the user relative to the displayed image is detected from an image of the eyeball obtained by capturing infrared light. Any known method can be used for gaze detection using an image of the eyeball. One example is a gaze detection method based on the Purkinje image formed by reflection of irradiated light on the cornea.

[0090] More specifically, gaze detection processing is performed based on the pupil-corneal reflex method, which calculates a gaze vector representing the direction (rotation angle) of the eyeball based on the pupil image and Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0091] A display device according to an embodiment of the present invention may have an imaging device having a light receiving element, and may control the image displayed on the display device based on information about the user's line of sight from the imaging device.

[0092] Specifically, the display device determines a first field of view area where the user gazes and a second field of view area other than the first field of view area based on the line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be determined by an external control device and received. In the display area of ​​the display device, the display resolution of the first field of view area may be controlled to be higher than the display resolution of the second field of view area. In other words, the resolution of the second field of view area may be lower than that of the first field of view area.

[0093] The display area includes a first display area and a second display area different from the first display area, and a high-priority area is determined from the first display area and the second display area based on line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be determined by an external control device and received. The resolution of the high-priority area may be controlled to be higher than the resolution of areas other than the high-priority area. In other words, the resolution of an area with a relatively low priority may be lowered.

[0094] Note that AI may be used to determine the first field of view area and areas with high priority. The AI ​​may be a model configured to estimate the angle of gaze and the distance to an object in the line of sight from an image of the eyeball, using as training data an image of the eyeball and the direction in which the eyeball in the image was actually looking. The AI ​​program may be included in the display device, the imaging device, or an external device. If included in an external device, it is transmitted to the display device via communication.

[0095] When display control is performed based on line-of-sight detection, it is preferably applicable to smart glasses that further include an imaging device for capturing images of the outside world. The smart glasses can display captured external information in real time.

[0096] As described above, by using a device using the organic light-emitting element according to this embodiment, it is possible to provide a stable display with good image quality even over a long period of time.

[0097] Next, an example of combining the display element of this embodiment with an eyepiece optical system that folds the optical path will be described.

[0098] FIG. 14 is a diagram showing the configuration of an HMD (head-mounted display) 101 as an image observation device of this embodiment. The HMD 101 is worn on the head of an observer. Reference numeral 102 denotes the observer's right eye, and reference numeral 103 denotes the observer's left eye. Display lenses 104 and 105 constitute an eyepiece optical system for the right eye OR1, and display lenses 106 and 107 constitute an eyepiece optical system for the left eye OL1. Each eyepiece optical system is a coaxial optical system made up of multiple (two) display lenses. The observer's right eye 102 is positioned at the exit pupil ER1 of the eyepiece optical system for the right eye OR1, and the observer's left eye 103 is positioned at the exit pupil EL1 of the eyepiece optical system for the left eye OL1.

[0099] Reference numeral 108 denotes a display element for the right eye, and reference numeral 109 denotes a display element for the left eye. Each of the display elements 108, 109 is a flat display element, and in this embodiment, an organic EL element is used. FIG. 15 is a diagram showing the appearance of the HMD 101 and a personal computer 150 connected thereto. Each display element displays a display image (original image) corresponding to an image signal output from the personal computer 150. The HMD 101 may be equipped with an image processing device inside and operate as a stand-alone device.

[0100] The eyepiece optical systems OR1 and OL1 guide light from the display elements 108 and 109 to the exit pupils ER1 and EL1, respectively, to project enlarged virtual images of the displayed image onto the observer's right eye 102 and left eye 103. This allows the observer to observe the (virtual image of) the displayed image displayed on the display elements 108 and 109 through the eyepiece optical systems OR1 and OL1.

[0101] In this embodiment, the focal length of each eyepiece optical system is 12 mm, the horizontal display angle of view is 45°, the vertical display angle of view is 34°, and the diagonal display angle of view is 54°. The eye relief E1, which is the distance between the surface of each eyepiece optical system closest to the exit pupil (the surface of the polarization separation element 114 described later on the exit pupil side) and the exit pupil of each eyepiece optical system, is 18 mm.

[0102] The right-eye and left-eye ocular optical systems OR1 and OL1 in this embodiment are optical systems that fold the optical path using polarized light, and their configuration will be explained using the right-eye ocular optical system OR1. The left-eye ocular optical system OL1 is similar, so its explanation will be omitted.

[0103] 16, the right-eye eyepiece optical system OR1 has, arranged in this order from the right-eye display element 108 toward the exit pupil ER1, a polarizing plate 110, a first phase plate 111, a display lens 105, a display lens 104, a second phase plate 113, and a polarization separation element (hereinafter referred to as PBS) 114. A half mirror 112 serving as a semi-transmissive reflective surface is formed on the surface of the display lens 104 facing the display element. The second phase plate 113 and the PBS 114 are stacked on the surface of the display lens 104 facing the exit pupil.

[0104] The polarizing plate 110, the first phase plate 111, the second phase plate 113, and the PBS 114 are all formed as flat plates. The polarization direction of the first linearly polarized light passing through the polarizing plate 110 is tilted at 45° from the slow axis of the first phase plate 111, and the polarization direction of the first linearly polarized light passing through the polarizing plate 110 is tilted at −45° from the slow axis of the second phase plate 113 (i.e., tilted at the same angle as the polarization direction of the first linearly polarized light, but in the opposite direction to the slow axis of the first phase plate 111). Furthermore, the polarization direction of the first linearly polarized light passing through the polarizing plate 110 and the polarization direction of the second linearly polarized light passing through the PBS 114 are perpendicular to each other.

[0105] Unpolarized light emitted from the right-eye display element 108 passes through the polarizing plate 110 to become linearly polarized light, passes through the first phase plate 111 to become circularly polarized light, and then passes through the display lens 105. The circularly polarized light then passes through the half mirror 112, the display lens 104, and the second phase plate 113 to become first linearly polarized light. This first linearly polarized light has a polarization direction orthogonal to the polarization direction of the light passing through the PBS 114, so it is reflected by the PBS 114 and passes through the second phase plate 113 to become circularly polarized light. This circularly polarized light then passes through the display lens 104, is reflected by the half mirror 112, passes through the display lens 104 again, and passes through the second phase plate 113 to become second linearly polarized light. This second linearly polarized light has a polarization direction that matches the polarization direction of the light passing through the PBS 114, so it passes through the PBS 114 and is directed to the exit pupil ER1 (right eye 102). Similarly, the light emitted from the left-eye display element 109 is guided to the exit pupil EL1 (left eye 103) by the left-eye eyepiece optical system OL1.

[0106] In this way, by configuring each eyepiece optical system to fold the optical path using polarization, it is possible to make each eyepiece optical system thinner in the optical axis direction, and to shorten the focal length of each eyepiece optical system, making it possible to observe images with a wide angle of view.

[0107] It is desirable for an HMD to be lightweight so that it can be worn by a viewer on the head. Therefore, it is desirable to manufacture the display lenses constituting the eyepiece optical system and the imaging lenses constituting the imaging optical system from resin, which has a lower specific gravity than glass. Therefore, in this embodiment, the display lenses 104 to 107 are resin lenses. Furthermore, the display lenses 104 and 106 closest to the exit pupil are plano-convex lenses having a convex surface facing the display element, and a half mirror 112 is provided on the convex surface, thereby achieving a wide angle of view while reducing the thickness of the eyepiece optical system. Furthermore, by making the convex surfaces of the display lenses 104 and 106 aspherical, the aberration correction effect is enhanced. Furthermore, the display lenses 105 and 107 are double-sided aspherical lenses made of resin, thereby enhancing the aberration correction effect.

[0108] However, the display lenses 105 and 107 may be glass lenses because they have a small outer diameter and have little effect on the weight. If the overall weight of the HMD 101 is within the allowable range, the display lenses 104 and 106 may also be glass lenses.

[0109] In the HMD 101 of this embodiment, it is desirable that the eye relief E1 is 15 mm or more so that even observers wearing glasses can wear it. On the other hand, if the eye relief is too long, the outer shape of the display lens becomes large and the HMD also becomes large, so it is desirable that the eye relief is 25 mm or less. In other words, the eye relief E1 is 15mm≦E1≦25mm (7) It is preferable to satisfy the following conditions.

[0110] 17, in the HMD 101 of this embodiment, when the eyeball (pupil) of the right eye 102 is facing (looking at) either the left or right edge of the display surface of the right-eye display element 108, the position of the exit pupil ER1' of the right-eye eyepiece optical system OR1, i.e., the eye relief E1', is set to 28 mm, which is the sum of the eyeball rotation radius of 10 mm and the eye relief E1 = 18 mm when the eyeball is facing the center of the display surface as shown in FIG. 14, and the exit pupil diameter is set to 6 mm. The same applies to the exit pupil of the left-eye eyepiece optical system OL1. By setting it in this way, even when the eyeball rotates to observe either the left or right edge (or similarly the top or bottom edge) of the display surface, light can be incident on the eyeball from the direction in which the eyeball is facing.

[0111] In an eyepiece optical system with a long eye relief, a short focal length, and a thin profile like the eyepiece optical system of this embodiment, the angle of emergence of light from the display element (display surface) becomes large at the peripheral angle of view of the display field. If the angle of emergence of light from the display surface becomes large, the viewing angle characteristics such as display luminance and display chromaticity decrease, resulting in a dark image or an inability to observe an image in the correct colors.

[0112] In the right-eye eyepiece optical system OR1, a ray that exits the right-eye display element (display surface) 108 and passes through the center of the exit pupil ER1 (ER1') of the eyepiece optical system OR1 is defined as a chief ray. In this embodiment, when the eyeball is facing the center of the display surface (hereinafter referred to as the front-viewing state) as shown in Fig. 14, the exit angles of the chief ray at the maximum horizontal peripheral angle of view of 22.5° are 18° and -18° at the right and left ends of the display element, respectively. On the other hand, when the eyeball is facing the right and left ends of the display surface in the horizontal direction (hereinafter referred to as the right-end viewing state and the left-end viewing state, respectively) as shown in Fig. 17, the exit angles of the chief ray at the maximum horizontal peripheral angle of view of 22.5° are 37° and -37°, respectively. In this embodiment, the angle of emergence from the display element (display surface) 108 of chief rays having a maximum peripheral angle of view of 17° in the vertical direction in the front-viewing state is 14°, and the absolute value of the angle of emergence from the display surface of chief rays having a maximum peripheral angle of view of 17° in the vertical direction when the eyeball is facing the top or bottom edge in the vertical direction (hereinafter referred to as the top-viewing state and bottom-viewing state) is 29°. However, the chief rays in the front-viewing state, top-viewing state, and bottom-viewing state are all designed to be inclined to the outside of the display element.

[0113] The emission angle from the display surface is normal to the substrate 8 (0°) at the center of the display element and increases approximately linearly with the display angle of view (position of the display element). The radiation direction is a direction tilting outward from the display element. Therefore, as shown in FIG. 7, it is desirable to arrange the microlenses of the display element so that the microlens displacement ΔML at the center of the display element is 0 and ΔML increases toward the edges. In other words, the microlenses and color filters are arranged so that the displacement to the right and left of the light-emitting region (pixel) increases toward the right and left edges of the display element in the horizontal direction. Similarly, the microlenses and color filters are arranged so that the displacement above and below the light-emitting region increases toward the top and bottom edges of the display element. In this embodiment, since the relationship between the maximum angle of view of the display device and the radiation angle of the chief ray is maintained as a roughly linear relationship in the left-right and up-down directions, if the amount of shift of the microlenses and color filters is determined so as to optimize the viewing angle characteristics at the horizontal ends (right-end viewing state and left-end viewing state) which are the maximum angle of view, the viewing angle characteristics at the upper and lower ends also take roughly optimal values. Hereinafter, in the results of the study of this embodiment, the characteristics of the right-end viewing state at the horizontal end position of the display element will be described.

[0114] Next, the generation of ghost light as unwanted light in the eyepiece optical systems OR1 and OL1 of this embodiment will be described with reference to Fig. 16. Here, the description will be given using the eyepiece optical system OR1 for the right eye, but the same applies to the eyepiece optical system OL1 for the left eye.

[0115] In the eyepiece optical system OR1 using polarized light as in this embodiment, due to birefringence in the display lenses 104 and 105 and the polarization characteristics of the polarizers 110, the phase plates 111 and 113, and the PBS 114, light emitted from the display element 108 may be guided directly to the viewer's right eye 102 without being reflected by the PBS 114, as shown in FIG. 18, rather than along the normal optical path shown in FIGS. 14 and 17. This light is called ghost light. This ghost light occurs when circularly polarized light passing through the first phase plate 111 becomes elliptically polarized due to birefringence in the display lenses 105 and 104, and the polarization direction of the linearly polarized light passing through the second phase plate 113 is tilted relative to its original direction, passing through the PBS 114, and being guided to the right eye 102. Even if there is no birefringence in the display lenses 104 and 105, ghost light can also occur if the polarization characteristics of the polarizers 110, the phase plates 111 and 113, and the PBS 114 are inaccurate.

[0116] In the case of ghost light shown in Fig. 18, the angle of emergence from display element (display surface) 108 of the chief ray at the maximum horizontal peripheral angle of view of 22.5° in the front viewing state is 11°, which is inclined on the opposite side to the normal to the display surface from the emergence angle of the normal chief ray shown in Fig. 14 and Fig. 17. Therefore, by shifting the microlenses of the light-emitting element to match the emergence angle of the normal chief ray as described above, not only can the viewing angle characteristics be improved but also the brightness of ghost light from the peripheral portion including the edge of the display element can be reduced.

[0117] Since birefringence within a lens generally increases from the center to the periphery of the lens, the intensity of ghost light due to birefringence within the lens also increases from the center to the periphery. Therefore, in order to reduce ghost light passing through the periphery of the lens, it is effective to reduce the brightness of light from the periphery of the display surface. In this embodiment, when the chief ray angle of normal light in the front-view state at the edge of the display element is θm and the radiation angle of ghost light is θg, it is desirable that the eyepiece optical system satisfy the following formula (8):

[0118] |θm - θg | ≧15° …(8) Next, we will explain the effects obtained by combining the display element of this embodiment with an eyepiece optical system. In this embodiment, we used the white-emitting organic EL element shown in Figure 3(b) and examined a configuration in which a color filter 20 was placed between the microlens 15 and the light-emitting region 17. Table 1 shows the values ​​of the microlens height h / D, radius r / D, and height L2 / D of the upper surface of the color filter normalized by the pixel pitch D.

[0119] [Table 1]

[0120] FIG. 19 shows the radiation angle dependence of the relative luminance ΔL in Comparative Example 1 and Example 1. Comparative Example 1 has a configuration in which the microlens displacement is zero. Example 1 has a configuration in which the microlenses are displaced, and the values ​​of the aperture ratio, φ1 (angle φ1), φ2 (angle φ2), and A are as shown in Table 2. The radiation angle on the horizontal axis is 0°, which is the direction in which the normal to the display surface of the display element 108 extends. When viewed with the right eye 102, the right side is positive and the left side is negative. The vertical axis represents the relative luminance, with the radiation light intensity at 0° in Comparative Example 1 being 1. Looking at the results of the comparative example in FIG. 19, the emission intensity decreases as the radiation angle increases, peaking at 0°. At a radiation angle of 37° for normal light in the right-edge viewing state, the emission intensity falls to 0.3. On the other hand, at a radiation angle of -11° for ghost light in the front viewing state, the emission intensity is high at 0.9. As such, the emission intensity in the direction causing the ghost is greater than the emission intensity of normal light. This is because, as shown in Figure 4B, when the microlens displacement ΔML is 0, light is focused in the normal direction of the substrate 8, reducing the amount of light emitted toward the wide-angle side, resulting in a higher emission intensity of ghost light compared to that of normal light. Generally, the emission intensity of light emitted from a finite light-emitting area decreases as the emission angle increases. Therefore, even in the configuration without microlenses shown in Figure 4A, the emission intensity of ghost light is similarly higher compared to that of normal light.

[0121] On the other hand, looking at the results of Example 1, the luminance intensity increases as the radiation angle relative to the radiation direction of normal light increases, reaching 0.85 at a radiation angle of 37° for normal light in the right-edge viewing state. On the other hand, the luminance intensity of ghost light significantly decreases to 0.32 at a radiation angle of -11° for ghost light in the front viewing state. Thus, the luminance intensity of normal light can be made higher than the luminance intensity in the direction that produces ghost light. The increase in the luminance intensity of normal light is due to the refraction of light 27 incident on surface 28, as shown in FIG. 4C. The decrease in the luminance intensity of ghost light is due to total reflection or refraction toward the wide-angle side occurring at surface 29 of the microlens of the adjacent light-emitting element, as shown in FIG. 4C. The φ1 in Example 1 shown here is 16.7, which satisfies Equation (5), which is the condition for the amount of microlens misalignment. Thus, by combining the polarized optical system shown in FIG. 14 with a display element in which the microlenses are misaligned to satisfy Equation (5), it is possible to increase the luminance intensity ΔL of normal light and simultaneously suppress ghost light.

[0122] [Table 2]

[0123] Next, the effect of the aperture ratio of the light-emitting element will be described. Table 3 shows the emission intensities ΔL of normal light and ghost light for Examples 1, 2, and 3, as examples where the aperture ratio is changed. The normal light intensity ΔL at an aperture ratio of 40% was 0.82, while it was 0.85 at an aperture ratio of 30% and 0.91 at an aperture ratio of 20%. By reducing the aperture ratio, the emission intensity of normal light increased. This is due to the increase in the ratio of area X to the area of ​​light-emitting region 17, as shown in FIG. 5A. This indicates that the light emitted from the light-emitting region is highly efficiently emitted in the normal light direction. Meanwhile, the emission intensity of ghost light was 0.40 at an aperture ratio of 40%, while it was 0.32 at an aperture ratio of 30%, and 0.22 at an aperture ratio of 20%. By reducing the aperture ratio, the emission intensity of ghost light decreased. This decrease in the emission intensity of ghost light is due to the smaller overlap between the sum of the ghost light emission regions Y1 and Y2 and the light-emitting region 17, as shown in FIG. 5B. That is, in the polarization optical system shown in FIG. 14, by reducing the aperture ratio under the condition that formula (5) is satisfied, it is possible to increase the normal light and reduce the ghost light.

[0124] [Table 3]

[0125] Next, the effect of the color filter shift amount ΔCF will be described based on Table 4. Table 4 shows the color shift ΔE of normal light and the emission intensity ΔL of ghost light when φ1 is fixed and φ2 is changed (when A is changed). Table 4 also shows Comparative Example 1 as a reference value.

[0126] The color shift ΔE is defined by the following formula (9), and is the change in hue in the a*b* space: Here, the reference values ​​a0 and b0 are the values ​​at 0° in Comparative Example 1.

[0127] ΔE=√((a-a0) 2 +(b-b0) 2 ) …(9) The color shift ΔE of normal light at A=0.84 was 20, while it was 18 at A=0.43 and 17 at A=0 (no color filter shift). In other words, the color shift ΔE of normal light decreased as the color filter shift amount decreased. This decrease in color shift is due to the light 33 emitted toward the wide-angle side being blocked by the adjacent color filter, as shown in Figure 6B. On the other hand, the color shift ΔE of ghost light was 0.32 at A=0.84, 0.32 at A=0.43, and 0.31 at A=0, indicating that it is independent of the color filter shift amount. This indicates that the color shift ΔE of normal light can be suppressed without increasing the emission intensity of ghost light. Setting A=0.85 or less reduces the color shift ΔE of normal light compared to when the microlens shift amount is 0. In other words, by satisfying the condition of formula (5) and also formula (6), the polarization optical system shown in FIG. 14 can ensure the emission intensity of normal light, suppress ghost light, and reduce the color shift ΔE.

[0128] [Table 4]

[0129] The above has described the effects of the polarized optical system shown in Figure 14. The results of this study are for the angle of the chief ray at the right end of the display element in the right-edge viewing state. However, if the maximum display angle of view is 60° or less, the viewer can also recognize the peripheral parts of the image in the straight-on viewing state. Therefore, the amount of misalignment of the microlenses and color filters may be determined assuming the straight-on viewing state, as long as formulas (5) and (6) are satisfied.

[0130] In this manner, in this embodiment, by shifting the microlenses relative to the pixels, it is possible to reduce ghost light while improving viewing angle characteristics such as brightness and color shift in the peripheral areas of the observed image.

[0131] Incidentally, birefringence within a lens is likely to occur when the lens is manufactured by molding a resin material into a mold, and the larger the lens thickness deviation ratio, the greater the difference in the way the thin and thick parts of the lens cool when cooled after molding into the mold, resulting in greater birefringence.

[0132] In a thin, wide-angle eyepiece optical system OR1 like the present embodiment, the display lens 104, which has the reflecting surface (half mirror 112) with the greatest optical power, has a large thickness deviation ratio. The thickness deviation ratio in the optically effective area of ​​the display lens 104 is 2.0, and it is desirable that the thickness deviation ratio be 1.5 or greater and 4 or less. If the thickness deviation ratio is less than 1.5, the optical power of the display lens 104 will be reduced, resulting in a larger radius of curvature or thickness of the display lens 104. If the optical power of the display lens 104 is reduced, it may be impossible to achieve a wide angle of view, or a lens with high optical power may need to be added, making it impossible to slim down the eyepiece optical system OR1. Furthermore, if the thickness of the display lens 104 is increased, it may be impossible to slim down the eyepiece optical system OR1. On the other hand, if the thickness deviation ratio is greater than 4, the birefringence of the display lens 104 will be too great, increasing the intensity of ghost light. Note that the optical paths of normal light and ghost light in the eyepiece optical system differ in the number of reflections within the eyepiece optical system.

[0133] If the thickness L1 of the eyepiece optical system OR1 is the distance from the surface of the PBS 114 on the exit pupil side to the display element 108, then the thickness L1 is 13 mm, and the ratio L1 / E1 of the thickness L1 to the eye relief E1 = 18 mm is 0.72. This value is set to achieve both an appropriate length of eye relief and a slim eyepiece optical system. 0.60≦L1 / E1≦1.00 …(10) It is desirable to satisfy the following condition. If L1 / E1 is smaller than 0.60, the eye relief becomes too long, which increases the outer diameter of the display lens and the size of the HMD 101, which is undesirable. Furthermore, the larger the outer diameter, the greater the birefringence of the display lens 104, which increases the intensity of ghost light. On the other hand, if L1 / E1 is larger than 1.00, the eyepiece optical system becomes thicker, which increases the size of the HMD 101, and the eye relief becomes too short, which may cause a feeling of oppression to the viewer or make it impossible for a viewer who wears glasses to wear the HMD. This is also undesirable.

[0134] In this embodiment, the maximum diagonal half angle of view θ1 of the eyepiece optical system OR1 is 27°. In this case, E1×tan θ1=9.2 mm. This value is set to achieve both an appropriate length of eye relief and a wide angle of view of the eyepiece optical system. 8mm≦E1×tanθ1≦20mm …(11) It is desirable to satisfy the following conditions. If E1 × tan θ1 is less than 8 mm, the eye relief will be too short, causing a sense of oppression to the viewer and making it impossible for viewers wearing eyeglasses to wear the device, which is undesirable. Furthermore, the display angle of view of the eyepiece optical system will be too narrow, preventing the viewer from viewing a realistic, natural image. On the other hand, if E1 × tan θ1 is greater than 20 mm, the eye relief will be too long, increasing the outer diameter of the display lens 104 and the size of the HMD 101, which is undesirable. Furthermore, the larger the outer diameter, the greater the birefringence of the display lens 104, resulting in increased intensity of ghost light. Furthermore, the display angle of view will be too wide, increasing the angle of emergence of the chief ray from the display surface at the peripheral angle of view, degrading the viewing angle characteristics.

[0135] Furthermore, in order to reduce ghost light caused by external light and increase the contrast of the image being observed, a polarizing plate may be disposed between the PBS 114 and the exit pupil of each eyepiece optical system.

[0136] Furthermore, in this embodiment, as shown in Fig. 16, the surface on the exit pupil side of the display lens 104, which is formed so that the second phase plate 113 and the PBS 114 are stacked, is made flat. This is to achieve both a long eye relief and a slimmer eyepiece optical system. If this surface has a concave shape toward the exit pupil, the display lens 104 will be thicker in order to ensure the eye relief at its periphery. On the other hand, if this surface has a convex shape toward the exit pupil, the display lens 104 will be thicker in order to ensure the thickness at its periphery.

[0137] In this embodiment, the first and second phase plates 111 and 113 are wave plates with a phase difference of λ / 4, but the phase difference may be shifted from λ / 4 so as to cancel the birefringence of the lenses 104 and 105. In this case, it is desirable that the sum of the phase differences of the lens 104 and the phase plate 113 be 3λ / 20 or more and 7λ / 20 or less. It is also desirable that the sum of the phase differences of the lens 105 and the first phase plate 111 be 3λ / 20 or more and 7λ / 20 or less. If the sum is outside this range, the intensity of ghost light increases, making it impossible to observe naturally. The conditions shown in equations (5) to (7), (10), and (11) described in this embodiment also apply to embodiment 2, which will be described later.

[0138] Furthermore, at least one or more of a second half mirror, a third phase plate, a second PBS, and a fourth phase plate may be further disposed between the first phase plate 111 and the half mirror 112. When a second half mirror is disposed, a convex surface may be additionally formed facing the display element side, and the second half mirror may be provided on the convex surface.

[0139] The third or fourth phase plate may be used as a variable phase plate in response to an electrical signal. For example, the phase difference of the phase plate may be switched so that when it is turned on, the half mirror 112 reflects normal light, and when it is turned off, the second half mirror reflects normal light. Furthermore, by switching between these settings, the device may be used as a foveated display, which time-division multiplexes high-resolution images for the central visual field and low-resolution images for the peripheral visual field. A variable-focus lens may be disposed inside or outside the half mirror 112 and the PBS 114. The variable-focus lens may be a glass lens, a polymer lens, a liquid crystal lens, or a combination thereof. The liquid crystal lens may be a Fresnel liquid crystal lens having a segmented parabolic phase shape, a Pancharatnum-Berry phase lens, or a combination thereof. Multiple Pancharatnum-Berry phase lenses may be stacked. A phase plate that can be switched on and off by an electrical signal may be additionally disposed on the Pancharatnum-Berry phase lens, or multiple Pancharatnum-Berry phase lenses and phase plates may be alternately stacked.

[0140] The preferred lens materials, shapes, etc. described in this embodiment are also the same in the second embodiment.

[0141] (Embodiment 2) Figure 20 shows the configuration of an HMD 201 according to a second embodiment of the present invention. Reference numeral 202 denotes the right eye of an observer, and reference numeral 203 denotes the left eye of the observer. Display lenses 204 and 205 constitute an eyepiece optical system for the right eye OR2, and display lenses 206 and 207 constitute an eyepiece optical system for the left eye OL2. Each eyepiece optical system is a coaxial optical system made up of two display lenses. The observer's right eye 202 is positioned at the exit pupil ER2 of the eyepiece optical system for the right eye OR2, and the observer's left eye 203 is positioned at the exit pupil EL2 of the eyepiece optical system for the left eye OL2.

[0142] Reference numeral 208 denotes a display element for the right eye, and reference numeral 209 denotes a display element for the left eye. Each display element is a flat-plate type display element, and in this embodiment, an organic EL display panel is used.

[0143] The eyepiece optical systems OR2 and OL2 guide light from the display elements 208 and 209 to the exit pupils ER2 and EL2, respectively, to project enlarged virtual images of the display images (original images) displayed on the display elements 208 and 209 onto the observer's right eye 202 and left eye 203. This allows the observer to observe the display images (virtual images) displayed on the display elements 208 and 209 through the eyepiece optical systems OR2 and OL2.

[0144] In this embodiment, the focal length of each eyepiece optical system is 13 mm, the horizontal display angle of view is 60°, the vertical display angle of view is 60°, and the diagonal display angle of view is 78°. The eye relief E2, which is the distance between the surface of each eyepiece optical system closest to the exit pupil (the surface of the polarization separation element 214, described later, closest to the exit pupil), is 20 mm.

[0145] Like in the first embodiment, the right-eye and left-eye eyepiece optical systems OR2 and OL2 in this embodiment are optical systems that fold the optical path using polarized light, and their configuration will be described using the right-eye eyepiece optical system OR2. As shown in Fig. 21 , the right-eye eyepiece optical system OR2 has a polarizing plate 210, a first phase plate 211, a display lens 205, a display lens 204, a second phase plate 213, and a PBS 214, which are arranged in this order from the right-eye display element 208 toward the exit pupil ER2. A half mirror 212 serving as a semi-transmissive reflective surface is formed by vapor deposition on the surface of the display lens 204 facing the display element. The second phase plate 213 and the PBS 214 are stacked on the surface of the display lens 204 facing the exit pupil.

[0146] The polarizing plate 210, the first phase plate 211, the second phase plate 213, and the PBS 214 are all formed in a flat plate shape. The polarization direction of the first linearly polarized light that transmits through the polarizing plate 210 is inclined at 45° from the slow axis of the first phase plate 211, and the polarization direction of the first linearly polarized light that transmits through the polarizing plate 210 is inclined at −45° from the slow axis of the second phase plate 213. Furthermore, the polarization direction of the first linearly polarized light that transmits through the polarizing plate 210 and the polarization direction of the second linearly polarized light that transmits through the PBS 214 are perpendicular to each other.

[0147] Unpolarized light emitted from the right-eye display element 208 passes through the polarizing plate 210 to become linearly polarized light, passes through the first phase plate 211 to become circularly polarized light, and then passes through the display lens 205. The circularly polarized light then passes through the half mirror 212, the display lens 204, and the second phase plate 213 to become first linearly polarized light. This first linearly polarized light has a polarization direction orthogonal to the polarization direction of the light passing through the PBS 214, so it is reflected by the PBS 214 and passes through the second phase plate 213 to become circularly polarized light. This circularly polarized light then passes through the display lens 204, is reflected by the half mirror 212, passes through the display lens 204 again, and passes through the second phase plate 213 to become second linearly polarized light. This second linearly polarized light has a polarization direction that matches the polarization direction of the light passing through the PBS 214, so it passes through the PBS 214 and is directed to the exit pupil ER2 (right eye 202). Similarly, the light emitted from the left-eye display element 209 is guided to the exit pupil EL2 (left eye 203) by the left-eye eyepiece optical system OL2.

[0148] In this embodiment, as in embodiment 1, each eyepiece optical system is configured to fold the optical path using polarized light, which makes it possible to make each eyepiece optical system thinner and shorten the focal length of each eyepiece optical system, making it possible to observe images with a wide angle of view.

[0149] In this embodiment, two display lenses are cemented together in each eyepiece optical system, making the thickness in the optical axis direction a slim 13.5 mm. As mentioned above, the eyepiece optical system has an eye relief E2 of 20 mm. By cementing the two display lenses together, the display lenses can be easily held by the main body of the HMD 201.

[0150] In this embodiment, the display lenses 204 to 207 are also made of resin lenses, and furthermore, the display lenses 204 to 207 are made of aspherical lenses to enhance the aberration correction effect.

[0151] Furthermore, since the display lenses 204 and 205 are cemented lenses, the half mirror 212 may be provided on the surface of the display lens 205 on the exit pupil side. Even in this case, the surface on which the half mirror is provided is convex toward the display element 208.

[0152] In the HMD 201 of this embodiment, as shown in Fig. 22, when the eyeball (pupil) of the right eye 202 is facing (looking at) either the left or right edge of the display surface of the display element 208, the position of the exit pupil ER2' of the eyepiece optical system OR2 for the right eye, i.e., the eye relief E2', is set to 30 mm, which is the sum of the eyeball rotation radius of 10 mm and the eye relief E2 = 20 mm when the eyeball is facing the center of the display surface as shown in Fig. 20, and the exit pupil diameter is set to 6 mm. The same applies to the exit pupil of the eyepiece optical system OL2 for the left eye. By setting it in this way, even when the eyeball rotates to observe either the left or right edge of the display surface (or similarly the top or bottom edge), light can be incident on the eyeball from the direction in which the eyeball is facing.

[0153] In the right-eye eyepiece optical system OR2, a ray that exits the right-eye display element (display surface) 208 and passes through the center of the exit pupil ER2 (ER2') of the eyepiece optical system OR2 is defined as a chief ray. In this embodiment, as shown in FIG. 20 , the exit angles of the chief ray at the maximum peripheral angle of view of 30° in the left-right direction (horizontal direction) in the front viewing state are 23° and −23° at the right and left ends of the display element, respectively. On the other hand, as shown in FIG. 22 , the exit angles of the chief ray at the maximum peripheral angle of view of 30° in the horizontal direction in the right-edge viewing state and the left-edge viewing state are 47° and −47°, respectively. In this embodiment, the exit angle of the chief ray at the maximum peripheral angle of view of 30° in the vertical direction in the front viewing state is 23°, and the absolute value of the exit angle of the chief ray at the maximum peripheral angle of view of 30° in the vertical direction in the top-edge viewing state and the bottom-edge viewing state is 47°. However, the chief ray in the front viewing state, top viewing state, and bottom viewing state is designed to fall outside the display element. In other words, this embodiment satisfies formula (8).

[0154] The emission angle from the display surface is in the substrate normal direction (0°) at the center of the display element and increases approximately linearly with the display angle of view. The radiation direction is a direction tilting outward from the display element 208. Therefore, as shown in FIG. 7, the microlens arrangement of the display element of this embodiment is preferably such that the microlens displacement amount ΔML is 0 at the center of the display element and ΔML increases toward the edges. In other words, the microlenses and color filters are arranged so that the amount of displacement to the right and left of the light-emitting region (pixel) increases toward the right and left edges of the display element in the horizontal direction. Similarly, the microlenses and color filters are arranged so that the amount of displacement above and below the light-emitting region increases toward the top and bottom edges of the display element. In this embodiment, the relationship between the maximum angle of view of the display device and the radiation angle of the chief ray is maintained as a roughly linear relationship in the left-right and up-down directions, so if the amount of shift of the microlenses and color filters is determined so as to optimize the viewing angle characteristics at the horizontal ends (right-end viewing state and left-end viewing state) which are the maximum angle of view, the viewing angle characteristics at the upper and lower ends will also take roughly optimal values. Hereinafter, in the results of the study of this embodiment, the characteristics of the right-end viewing state at the horizontal end position of the display element will be explained.

[0155] Ghost light also occurs in the eyepiece optical systems OR2 and OL2 of this embodiment for the same reasons as in Embodiment 1. As shown in Fig. 23, the angle of emergence from the display element (display surface) 208 of the chief ray at the maximum horizontal peripheral angle of view of 30° in the front viewing state is 15°, which is tilted on the opposite side to the normal to the display surface from the angle of emergence of the normal chief ray shown in Figs. 20 and 22. Therefore, by shifting the microlenses relative to the light-emitting elements to match the angle of emergence of the normal chief ray as described above, not only can the viewing angle characteristics be improved but also the brightness of ghost light from the peripheral portion, including the edges of the display surface, can be reduced.

[0156] Next, we will explain the effects obtained by combining the display element of this embodiment with the eyepiece optical system. As mentioned above, we will explain the characteristics of the right-edge viewing state at the horizontal edge position of the display element. In this study, as in embodiment 1, we used a configuration in which a white-emitting organic EL element shown in Figure 3(b) was used and a color filter 20 was placed between the microlens 15 and the light-emitting region 17. The height h / D of the microlens, normalized by the pixel pitch D, its radius r / D, and the height L2 / D of the upper surface of the color filter are the same as in embodiment 1.

[0157] Table 5 shows the radiation angle dependence of the relative luminance ΔL for Comparative Example 1 and Example 6. Comparative Example 1 has a configuration in which the microlens displacement is zero. Example 6 has a configuration in which the microlenses are displaced, and the values ​​of the aperture ratio, φ1, φ2, and A are as shown in Table 5. Referring to FIG. 19 showing the values ​​in Table 5 and the results of Example 1, in Comparative Example 1, the luminance intensity peaks at 0° and decreases as the radiation angle increases, dropping to 0.09 at a radiation angle of 47° for normal light in the right-edge viewing state. On the other hand, the luminance intensity is high at 0.82 at a radiation angle of -15° for ghost light in the front viewing state. As such, the luminance intensity in the direction of the ghost is greater than that of normal light.

[0158] This is because, as shown in Figure 4B, when the microlens displacement ΔML is 0, light is focused in the normal direction of the substrate 8, reducing the amount of light emitted toward the wide-angle side, resulting in a higher emission intensity of ghost light compared to that of normal light. Generally, the emission intensity of light emitted from a finite light-emitting area decreases as the emission angle increases. Therefore, even in the configuration without microlenses shown in Figure 4A, the emission intensity of ghost light is similarly higher compared to that of normal light.

[0159] On the other hand, looking at the results of Example 6, the luminance intensity increases with the direction of radiation of normal light, reaching 0.65 at a radiation angle of 47° for normal light in the right-edge viewing state. On the other hand, at a radiation angle of -15° for ghost light in the front viewing state, the luminance intensity significantly decreases to 0.23. Thus, the luminance intensity of normal light can be made greater than the luminance intensity in the direction that produces ghost light. The increase in the luminance intensity of normal light is due to the refraction of light 27 incident on surface 28, as shown in FIG. 4C. The decrease in the luminance intensity of ghost light is due to total reflection or refraction toward the wide-angle side occurring at surface 29 of the microlens of the adjacent light-emitting element, as shown in FIG. 4C. The φ1 in Example 6 shown here is 16.7, which satisfies Equation (5), which is the condition for the amount of microlens misalignment. Thus, by combining the polarized optical system shown in FIG. 20 with a display element in which the microlenses are misaligned to satisfy Equation (5), it is possible to increase the luminance intensity ΔL of normal light and simultaneously suppress ghost light.

[0160] [Table 5]

[0161] Next, the effect of the aperture ratio of the light-emitting element will be described. Table 6 shows the emission intensities ΔL of normal light and ghost light in Examples 6 to 8 as examples where the aperture ratio was changed. The normal light intensity ΔL at an aperture ratio of 40% was 0.71, while it was 0.75 at an aperture ratio of 30% and 0.94 at an aperture ratio of 20%. Thus, by reducing the aperture ratio, the emission intensity of normal light increases. This is due to the increase in the ratio of area X to the area of ​​light-emitting region 17, as shown in FIG. 5A. This indicates that the light emitted from light-emitting region 17 is radiated in the normal light direction with high efficiency. Meanwhile, the emission intensity of ghost light was 0.30 at an aperture ratio of 40%, while it was 0.27 at an aperture ratio of 30%, and 0.17 at an aperture ratio of 20%. Thus, it was found that the emission intensity of ghost light decreased by reducing the aperture ratio. This decrease in the emission intensity of ghost light is due to the decrease in the overlap between the sum of the ghost light emission regions Y1 and Y2 and the light-emitting region 17, as shown in FIG. 5B. 20 to 22, it is possible to increase the normal light and reduce the ghost light by reducing the aperture ratio while satisfying the condition of formula (5). In order to increase the normal light and reduce the ghost light, it is desirable to set the aperture ratio to 52% or less.

[0162] [Table 6]

[0163] Next, Table 7 shows the effect of the color filter shift amount ΔCF. Table 7 shows the color shift ΔE of normal light and the emission intensity ΔL of ghost light when φ1 is fixed and φ2 is changed (when A is changed). Table 7 also shows Comparative Example 1 as a reference value.

[0164] The color shift ΔE of normal light at A = 0.64 was 31, while it was 28 at A = 0.33 and 25 at A = 0 (no color filter shift). In other words, reducing the color filter shift reduced the color shift ΔE of normal light. Furthermore, since Examples 6, 9, and 10 satisfy Equation (6), they also had smaller color shift ΔE than Comparative Example 1. This reduction in color shift is due to the light 33 emitted toward the wide-angle side being blocked by adjacent color filters, as shown in Figure 6B. On the other hand, the ghost light was 0.23 at A = 0.64, 0.28 at A = 0.28, and 0.24 at A = 0, indicating that the color shift ΔE of normal light can be reduced without increasing the emission intensity of the ghost light. Setting A = 0.85 or less reduces the color shift ΔE of normal light compared to when the microlens shift amount is 0. In other words, by satisfying the condition of equation (5) as well as equation (6), it is possible to increase the emission intensity of normal light and suppress ghost light in the polarized optical system shown in Figure 20, while also reducing the color shift ΔE.

[0165] [Table 7]

[0166] When the maximum display angle of view is greater than 60°, the wide angle of view makes it difficult for the viewer to recognize the peripheral parts of the image when viewing from the front. For this reason, it is preferable to determine the amount of color filter offset based on the angle of emergence of the chief ray from the display surface in the direction of viewing when viewing the peripheral parts of the image, rather than when viewing from the front. However, depending on the lens design, light may be vignetted at the edges of the display element, so it is not necessarily necessary to align the color filters with the edges.

[0167] In this embodiment, too, the eyepiece optical system OR2 for the right eye has a wide angle of view and is thin, so the display lens 204, which has the reflecting surface (half mirror 212) with the greatest optical power, has a large thickness deviation ratio. Because the display lenses 204 and 205 are cemented together, the radius of curvature of the cemented surface of the display lens 205 with the display lens 204 is short, and the thickness deviation ratio of the display lens 205 is also large. In this embodiment, the thickness deviation ratio in the optically effective area of ​​the display lens 204 is 3.6, and the thickness deviation ratio in the optically effective area of ​​the display lens 205 is 2.8. As explained in the first embodiment, it is desirable that these thickness deviation ratios be 1.5 or more and 4 or less.

[0168] Furthermore, if the thickness L2 of the right-eye eyepiece optical system OR2 is defined as the distance from the surface of the PBS 214 on the side of the observer's right eye 202 to the right-eye display element 208, then the thickness L2 is 13.5 mm, and the ratio of the thickness L2 to the eye relief E2, L2 / E2, is 0.68. This value is preferably between 0.6 and 1 in order to achieve both an appropriate eye relief length and a slim eyepiece optical system.

[0169] In this embodiment, the eye relief E2 of the right-eye eyepiece optical system OR2 is 20 mm, and the maximum diagonal half angle of view θ2 is 39°. In this case, E2×tan θ2=16.2 mm, which satisfies the condition of formula (11). The thickness deviation ratios L2 / E2 and E2×tan θ2 are the same for the left-eye eyepiece optical system OL2.

[0170] Also in this embodiment, a polarizing plate may be disposed between the PBS 214 and the exit pupil of each eyepiece optical system in order to reduce ghost light caused by external light and increase the contrast of the image being observed.

[0171] (Embodiment 3) Next, a description will be given of the configuration of an HMD 301 according to embodiment 3. Fig. 24 is a diagram showing the eyepiece optical system of the HMD 301. In the figure, reference numeral 302 denotes the right eye of the observer, reference numeral 303 denotes the left eye of the observer, reference numeral 304 denotes the eyepiece optical system for the right eye, reference numeral 305 denotes the eyepiece optical system for the left eye, reference numeral 306 denotes an image display element for the right eye, and reference numeral 307 denotes an image display element for the left eye.

[0172] The right-eye eyepiece optical system 304 enlarges and projects the original image displayed on the right-eye image display element 306 and directs it to the observer's right eye 302, while the left-eye eyepiece optical system 305 enlarges and projects the original image displayed on the left-eye image display element 307 and directs it to the observer's left eye 303. The right-eye eyepiece optical system 304 and the left-eye eyepiece optical system 305 have a horizontal display angle of view of 40°, a vertical display angle of view of 30°, and a diagonal display angle of view of 50°.

[0173] The eyepiece optical system of this embodiment is thinned by folding the optical path using a decentered reflecting surface, as shown in Figure 25. The eyepiece optical system 304 for the right eye is made of a transparent body filled with an optical medium such as glass or plastic with a refractive index greater than 1. The same is true for the eyepiece optical system for the left eye.

[0174] Light rays from the right-eye image display element 306 are reflected twice within the right-eye eyepiece optical system 304 and directed to the right eye 302. Note that the exit surface of the right-eye eyepiece optical system 304 to the eyeball is an optical surface that has both reflecting and transmitting functions, so it is desirable that the reflection be total internal reflection to eliminate loss of light. Furthermore, by making the surfaces that make up the right-eye eyepiece optical system 304 free-form, the degree of freedom in correcting decentering aberrations increases, enabling images to be displayed with good image quality. The same is true for the left-eye eyepiece optical system 305.

[0175] As with embodiments 1 and 2, the eyepiece optical system of this embodiment has a large output angle from the image display element at the peripheral angle of view, which raises concerns that the viewing angle characteristics will deteriorate in the peripheral areas, resulting in reduced brightness and making it impossible to observe images in the correct colors.

[0176] In the eyepiece optical system of this embodiment, when the observer is looking straight ahead, as shown in FIG. 24, the exit angle from the image display element of the chief ray for the maximum horizontal peripheral angle of view of 20° is 20°. Also, as shown in FIG. 24, when the observer is looking at a horizontal edge, the exit angle from the image display element of the chief ray for the maximum horizontal peripheral angle of view of 20° is 30°. Here, the chief ray is a ray that passes through the center of the exit pupil of the eyepiece optical system. While the explanation so far has been given for the left and right edges in the horizontal direction, the same applies to the top and bottom edges in the vertical direction. In the eyepiece optical system of this embodiment, when the observer is looking straight ahead, as shown in FIG. 25, the exit angle from the image display element of the chief ray for the maximum vertical peripheral angle of view of 15° is 15°. Also, as shown in FIG. 26, when the observer is looking at a vertical edge, the exit angle from the image display element of the chief ray for the maximum vertical peripheral angle of view of 15° is 22.5°. However, the chief ray is designed to be tilted outside the display element in the front viewing state, right edge viewing state, left edge viewing state, top edge viewing state, and bottom edge viewing state. The exit angle from the display surface is normal to the substrate 8 (0°) at the center of the display element, and increases approximately linearly with the display angle of view.

[0177] The radiation direction is the direction inclined outward from the display element. Therefore, as shown in FIG. 7 , the microlens arrangement of the display element of this embodiment is preferably such that the microlens offset ΔML at the center of the display element is 0 and ΔML increases toward the edges. That is, toward the right and left edges of the display element in the horizontal direction, the microlenses and color filters are arranged so that the offset to the right and left of the light-emitting region (pixel) increases. Similarly, toward the top and bottom edges of the display element, the microlenses and color filters are arranged so that the offset to the top and bottom of the light-emitting region increases. In this embodiment, the relationship between the maximum field angle and the radiation angle of the chief ray of light in the display device is generally linear in the horizontal and vertical directions. Therefore, if the offset of the microlenses and color filters is determined to optimize the viewing angle characteristics in the direction in which ghosting occurs, i.e., the top-end viewing state and the bottom-end viewing state, the viewing angle characteristics at the horizontal edge will also be generally optimal. Hereinafter, the results of this embodiment will be described with respect to the characteristics of the display element in the bottom-end viewing state in the vertical direction.

[0178] In the eyepiece optical system of this embodiment, ghost light is generated with an optical path as shown in FIG. 27. The optical path of ghost light from the upper end of the image display element is shown in FIG. 27(a), and the optical path of ghost light from the lower end of the image display element is shown in FIG. 27(b). In the optical path of ghost light shown in FIG. 27(a), the angle of emergence θ3 of the chief ray from the upper end of the image display element 306 is −28° when the observer is looking straight ahead. Also, in the optical path of ghost light shown in FIG. 27(b), the angle of emergence θ3 of the chief ray from the lower end of the image display element is −34° when the observer is looking straight ahead. In other words, this embodiment satisfies formula (8).

[0179] Next, we will explain the effects obtained by combining the display element of this embodiment with an eyepiece optical system. As mentioned above, we will explain the characteristics of the bottom viewing state when the display element is in a vertical position. In this study, as in embodiment 1, we used an organic electroluminescent element that emits white light as shown in Figure 3(b), and a configuration in which a color filter 20 is placed between the microlens 15 and the light-emitting region 17. The height h / D of the microlens, normalized by the pixel pitch D, its radius r / D, and the height L2 / D of the upper surface of the color filter are the same as in embodiment 1.

[0180] Table 8 shows the radiation angle dependence of the relative luminance ΔL of Comparative Example 1 and Example 11. Comparative Example 1 has a configuration in which the amount of displacement of the microlenses is zero. Example 11 has a configuration in which the microlenses are displaced, and the values ​​of the aperture ratio, φ1, φ2, and A are as shown in Table 8. Referring to FIG. 19 showing the values ​​in Table 8 and the results of Example 1, in Comparative Example 1, the luminous intensity peaks at 0° and decreases as the radiation angle increases, dropping to 0.6 at a radiation angle of 22.5° for normal light in the bottom viewing state. On the other hand, at a radiation angle of -34° for ghost light in the front viewing state, the luminous intensity is high at 0.47.

[0181] On the other hand, looking at the results of Example 11, the luminance intensity increases with the direction of radiation of normal light, reaching 1.0 at a radiation angle of 22.5° for normal light in the right-edge viewing state. On the other hand, at a radiation angle of -34° for ghost light in the front viewing state, the luminance intensity significantly drops to 0.23. Thus, the luminance intensity of normal light can be made greater than the luminance intensity in the direction that produces ghost light. The increase in the luminance intensity of normal light is due to the refraction of light 27 incident on surface 28, as shown in FIG. 4C. The decrease in the luminance intensity of ghost light is due to total reflection or refraction toward the wide-angle side occurring at surface 29 of the microlens of the adjacent light-emitting element, as shown in FIG. 4C. In Example 11 shown here, φ1 is 11.3, which satisfies Equation (5), which is the condition for the amount of microlens misalignment. Thus, by combining the polarized optical system shown in FIG. 24 with a display element in which the microlenses are misaligned to satisfy Equation (5), it is possible to increase the luminance intensity ΔL of normal light and simultaneously suppress ghost light.

[0182] [Table 8]

[0183] Next, the effect of the aperture ratio of the light-emitting element will be described. Table 9 shows the emission intensities ΔL of normal light and ghost light in Examples 11 to 13 as examples where the aperture ratio was changed. The normal light intensity ΔL was 0.93 at an aperture ratio of 40%, 0.94 at an aperture ratio of 30%, and 1.00 at an aperture ratio of 20%. Thus, by reducing the aperture ratio, the emission intensity of normal light increases. This is due to the increase in the ratio of area X to the area of ​​light-emitting region 17, as shown in FIG. 5A. This indicates that the light emitted from the light-emitting region is highly efficiently emitted in the normal light direction. Meanwhile, the emission intensity of ghost light was 0.31 at an aperture ratio of 40%, 0.23 at an aperture ratio of 30%, and 0.16 at an aperture ratio of 20%. Thus, it was found that the emission intensity of ghost light decreased by reducing the aperture ratio. This decrease in the emission intensity of ghost light is due to the smaller overlap between the sum of the ghost light emission regions Y1 and Y2 and the light-emitting region 17, as shown in FIG. 5B. That is, in the free curved surface prisms shown in FIGS. 24 to 26, by reducing the numerical aperture under the condition that formula (5) is satisfied, it is possible to increase the normal light and reduce the ghost light.

[0184] [Table 9]

[0185] Next, Table 10 shows the effect of the color filter shift amount ΔCF. Table 10 shows the color shift ΔE of normal light and the emission intensity ΔL of ghost light when φ1 is fixed and φ2 is changed (when A is changed). Table 10 also shows Comparative Example 1 as a reference value.

[0186] The color shift ΔE of normal light at A = 0.63 was 7, while it was 6 at A = 0.00 (no color filter shift). In other words, by reducing the color filter shift amount, the color shift ΔE of normal light was reduced. Furthermore, since Examples 11 and 14 satisfy formula (6), the color shift ΔE is smaller than that of Comparative Example 1. This reduction in color shift is due to the light 33 emitted toward the wide-angle side being blocked by the adjacent color filter, as shown in Figure 6B. On the other hand, the ghost light was 0.23 at A = 0.63 and 0.22 at A = 0, indicating that it is not dependent on the color filter shift amount. This indicates that the color shift ΔE of normal light can be suppressed without increasing the emission intensity of the ghost light. By setting A = 0.85 or less, the color shift ΔE of normal light can be reduced compared to when the microlens shift amount is 0. In other words, by satisfying the condition of equation (5) as well as equation (6), it is possible to increase the emission intensity of normal light and suppress ghost light while reducing color shift ΔE in the free-form surface prisms shown in Figures 24 to 26.

[0187] [Table 10]

[0188] In this way, in this embodiment, by shifting the microlenses relative to the pixels, it is possible to reduce ghost light while improving viewing angle characteristics such as brightness and color shift in the peripheral areas of an image observed through an eyepiece optical system using a free-form surface prism.

[0189] Although the free-form surface prism of the eyepiece optical system in the above embodiment does not have an intermediate image plane, it may be an optical system that has an intermediate image plane. Also, the free-form surface prism may be used as an optical element that is coupled to the display surface of a display element and a waveguide combiner. [Explanation of symbols]

[0190] 101, 201: HMD, 108, 208: Right-eye display element, 109, 209: Left-eye display element, OR1, OR2: Right-eye contact optical system, OL1, OL2: Left-eye contact optical system, 1000: Display device, 1100: Imaging device, 1200: Electronic equipment, 1500: Automobile, 1600, 1610: Speedgraph

Claims

1. a display element including a plurality of light-emitting elements arranged two-dimensionally on a plane, a plurality of microlenses provided corresponding to the plurality of light-emitting elements, and a color filter disposed between the light-emitting elements and the microlenses; an eyepiece optical system having at least one reflecting surface therein and directing light from the display surface of the display element to an exit pupil; In a display device, in a peripheral portion of the display element, a light emitting center of the light emitting element and a center of the microlens corresponding to the light emitting element are misaligned in a direction parallel to the plane, When the height of the microlens is h, the height from the surface of the opening of the light-emitting element to the bottom surface of the microlens is L, the amount of deviation between the center of the light-emitting element in the peripheral part of the display element and the center of the microlens in the direction parallel to the plane is ΔML, and the angle φ1 determined by the height h, the height L, and the amount of deviation ΔML is φ1=arctan(ΔML / (h+L)), then φ1 is 6.0°≦φ1≦37.5° Fulfilling When the height from the surface of the opening of the light-emitting element to the upper surface of the color filter is L2, the amount of deviation between the light-emitting center of the light-emitting element in the peripheral part of the display element and the center of the color filter in the direction parallel to the plane is ΔCF, the angle determined by the height L2 and the amount of deviation ΔCF is φ2=arctan(ΔCF / L2), and the ratio A of the angle φ1 to the angle φ2 is A=φ2 / φ1, A is 0≦A≦0.85 A display device characterized by satisfying the above.

2. 2. The display device according to claim 1, wherein all of the plurality of microlenses satisfy the condition for φ1.

3. In the peripheral portion of the display element, when the radiation angle of the chief ray of the normal light is θm and the radiation angle of the ghost light is θg, θm and θg are expressed as follows: |θm - θg | ≧15° 3. The display device according to claim 1, wherein the following is satisfied:

4. 4. A display device according to claim 1, wherein the light-emitting center of the light-emitting element and the center of the microlens corresponding to the light-emitting element are offset in a direction parallel to the plane in the peripheral portion of the display element so that the emission intensity of normal light from the peripheral portion of the display element that has passed through the eyepiece optical system increases and the emission intensity of ghost light from the peripheral portion of the display element that has passed through the eyepiece optical system decreases.

5. 5. A display device according to claim 1, wherein the eyepiece optical system comprises, in order from the display element toward the exit pupil, a first phase plate, a semi-transmissive reflective surface, at least one lens, and a polarization separation element that reflects first linearly polarized light and transmits second linearly polarized light having a polarization direction perpendicular to the polarization direction of the first linearly polarized light.

6. 6. The display device according to claim 5, wherein the semi-transmissive reflective surface is provided on a surface of the lens, and the surface is convex toward the display element.

7. 6. The display device according to claim 5, wherein the semi-transmissive reflective surface is provided on the surface of the lens, and the surface is aspherical.

8. 8. The display device according to claim 5, wherein the lens closest to the exit pupil among the at least one lens is a plano-convex lens having a convex surface facing the display element.

9. 9. The display device according to claim 5, wherein the thickness deviation ratio in the optically effective area of ​​the at least one lens is 1.5 or more and 4 or less.

10. 10. The display device according to claim 5, wherein the eyepiece optical system has a polarizing plate between the polarization separation element and the exit pupil that transmits the second linearly polarized light.

11. 11. The display device according to claim 5, wherein the eyepiece optical system has a polarizing plate between the display element and the first phase plate that transmits the first linearly polarized light.

12. 12. The display device according to claim 1, wherein the eyepiece optical system is a free-form prism.

13. 13. The display device according to claim 1, wherein the eyepiece optical system has at least two reflecting surfaces therein.

14. 14. The display device according to claim 13, wherein the number of reflections within the eyepiece optical system is different between the optical path of normal light and the optical path of ghost light in the eyepiece optical system.

15. 15. A display device according to claim 1, wherein the amount of deviation between the light-emitting center of the light-emitting element and the center of the microlens corresponding to the light-emitting element in a direction parallel to the plane increases from the center of the display element toward the periphery, and the change in the amount of deviation is constant or increases.

16. 16. The display device according to claim 1, wherein the aperture ratio of the light-emitting element is 52% or less.

17. The eye relief E1 of the eyepiece optical system is 15 mm ≦ E1 ≦ 25 mm 17. The display device according to claim 1, wherein the following is satisfied:

18. The thickness L1 of the eyepiece optical system and the eye relief E1 of the eyepiece optical system are 0.6≦L1 / E1≦1.0 18. The display device according to claim 1, wherein the following is satisfied:

19. The eye relief E1 of the eyepiece optical system and the maximum diagonal half angle of view θ of the eyepiece optical system are 8 mm ≦ E1 × tanθ ≦ 20 mm 19. The display device according to claim 1, wherein the following is satisfied:

20. 20. The display device according to claim 1, wherein the center of the microlens is the center of gravity of a shape formed by lines connecting the ends in a plan view.

21. 21. The display device according to claim 1, wherein the display surface of the display element is an n-sided polygon (n≧5).

22. 22. The display device according to claim 1, wherein either or both of the light-emitting elements and the microlenses are not disposed in at least one diagonal region of the display element.

23. the eyepiece optical system includes a first lens and a second lens disposed between the first lens and the display element, a first phase plate between the second lens and the display element, and a second phase plate on an exit pupil side of the first lens; 23. The display device according to claim 1, wherein the first phase plate and the second phase plate are arranged so as to cancel birefringence of the first lens and the second lens.

24. the eyepiece optical system includes a first lens and a second lens disposed between the first lens and the display element, a first phase plate between the second lens and the display element, and a second phase plate on an exit pupil side of the first lens; 24. The display device according to claim 1, wherein a sum of phase differences between the first lens and the second phase plate is 3[lambda] / 20 or more and 7[lambda] / 20 or less.

25. the eyepiece optical system includes a first lens and a second lens disposed between the first lens and the display element, a first phase plate between the second lens and the display element, and a second phase plate on an exit pupil side of the first lens; 25. The display device according to claim 1, wherein a sum of phase differences between the second lens and the first phase plate is 3[lambda] / 20 or more and 7[lambda] / 20 or less.

Images