Optical Department

Abstract

To provide an optical system that enables miniaturization and improved mass production. [Solution] The optical system 3 comprises a deflection unit 4 that dynamically deflects an incident light beam L1, and an optical element 5 having a plurality of unit optical elements 51. Each of the plurality of unit optical elements 51 includes an incident part 511 into which a light beam L2 from the deflection unit 4 is incident, a reflecting part 512 that reflects the light beam L2 incident from the incident part 511, and an outgoing part 513 that emits the light beam L3 reflected by the reflecting part 512. In each of the plurality of unit optical elements 51, the reflecting part 512 has two or more reflective surfaces 512a, 512b that reflect the light beam L2 incident from the incident part 511 an even number of times, such that the light beam L3 from the outgoing part 513 is directed toward a focusing position P that is plane-symmetric with respect to the deflection unit 4 with respect to a virtual plane S between the incident part 511 of the plurality of unit optical elements 51 and the outgoing part 513 of the plurality of unit optical elements 51.

Description

[Technical Field]

[0001] This disclosure relates to an optical system. [Background technology]

[0002] Patent Document 1 discloses an image display device. The image display device disclosed in Patent Document 1 comprises a display element and an optical system. The optical system comprises a light guide member and a projection optical system. The projection optical system projects a light beam (image light) from the display element. The light guide member guides the light beam projected by the projection optical system into the user's field of view. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] International Publication No. 2022 / 185609 [Overview of the project] [Problems that the invention aims to solve]

[0004] In practical terms, projection optics are constructed using multiple optical components, which inevitably leads to the optics themselves becoming larger. Furthermore, as the number of optical components in a projection optics increases, aligning the positions of the components becomes more difficult, which contributes to a decrease in the mass-producibility of the optics.

[0005] This disclosure provides an optical system that enables miniaturization and improved mass production. [Means for solving the problem]

[0006] An optical system relating to one aspect of this disclosure is A deflection unit that dynamically deflects the incident light beam, An optical element having multiple unit optical elements, Equipped with, Each of the multiple unit optical elements is, The incident section into which the light beam from the deflection section enters, A reflecting section that reflects the light beam incident from the incident section, an emission section that emits the light beam reflected by the reflection section; comprising in each of the plurality of unit optical elements, the reflection section has two or more reflection surfaces that reflect the light beam incident from the incidence section an even number of times, such that the light beam from the emission section travels toward a light condensing position that is plane-symmetric to the deflection section with respect to a virtual plane between the incidence sections of the plurality of unit optical elements and the emission sections of the plurality of unit optical elements.

Effects of the Invention

[0007] Aspects of the present disclosure enable reduction in size and improvement in mass productivity.

Brief Description of Drawings

[0008] [Figure 1] Schematic perspective view of an image display device provided with the optical system according to the first embodiment [Figure 2] Side view of the image display device according to the first embodiment [Figure 3] Plan view of the image display device according to the first embodiment with a part omitted [Figure 4] Schematic perspective view of an optical element of the optical system according to the first embodiment [Figure 5] Schematic perspective view of a unit optical element of the optical element of the optical system according to the first embodiment [Figure 6] Explanatory view of the arrangement of unit optical elements of the optical system according to the first embodiment [Figure 7] Explanatory view of an optical path in the unit optical element of the optical system according to the first embodiment [Figure 8] Explanatory view of an optical path in the unit optical element of the optical system according to the first embodiment [Figure 9] Explanatory view of an optical path in the unit optical element of the optical system according to the first embodiment [Figure 10] Schematic perspective view of a light guide member of the optical system according to the first embodiment [Figure 11] Schematic perspective view of an image display device provided with the optical system according to the second embodiment [Figure 12] Side view of the optical system according to the second embodiment [Figure 13]Side view of an optical system in one modified example. [Figure 14] Schematic perspective view of an optical element in one modified example. [Figure 15] Schematic perspective view of a unit optical element in Figure 14. [Modes for carrying out the invention]

[0009] [1. Embodiments] The embodiments of this disclosure will be described below, with reference to the drawings as appropriate. However, the embodiments described below are illustrative examples for illustrating this disclosure and are not intended to limit this disclosure to the following (for example, the shape, dimensions, arrangement, etc., of each component). Unless otherwise specified, positional relationships such as up, down, left, and right shall be based on the positional relationships shown in the drawings. The figures described in the embodiments below are schematic diagrams, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the dimensional ratios of each element are not limited to the ratios shown in the drawings.

[0010] In the following explanation, when it is necessary to distinguish between multiple components, prefixes such as "1st," "2nd," etc., will be added to the names of the components. However, if the components can be distinguished from each other by the symbols attached to them, prefixes such as "1st," "2nd," etc., may be omitted for the sake of readability.

[0011] In the following explanation, when it is necessary to distinguish between multiple components, suffixes such as "-1" and "-2" will be added to the component symbols. However, when it is not necessary to distinguish between multiple components, suffixes such as "-1" and "-2" may be omitted for the sake of readability.

[0012] In this disclosure, expressions such as "directing light in the direction of XX" and "propagating light in the direction of XX" mean that the light that forms the image as a whole is directed in the direction of XX, and the rays included in the light that forms the image may be inclined with respect to the direction of XX. For example, "light directed in the direction of XX" means that the principal ray of the light is directed in the direction of XX, and the secondary ray of the light may be inclined with respect to the direction of XX.

[0013] [1.1 Embodiment 1] [1.1.1 Configuration] Figure 1 is a schematic perspective view of an image display device 1 equipped with an optical system 3 according to this embodiment. Figure 2 is a side view of the image display device 1. Figure 3 is a plan view of the image display device 1 with a portion omitted.

[0014] The image display device 1 further includes a light source 2. The image display device 1 is, for example, a head-mounted display (HMD) that is worn on the user's head and displays images (video).

[0015] Light source 2 emits a directional beam of light L1 for forming an image. Light source 2 may include a laser light source. Examples of laser light sources include semiconductor lasers and laser oscillators (such as solid-state lasers). Light source 2 may optionally include collimating means to collimate the beam of light L1 emitted from the laser light source into substantially parallel light. The collimating means may consist of, for example, an aspherical lens or a plurality of spherical lenses. Alternatively, they may be integrated into a lens array.

[0016] The optical system 3 is configured to guide the light beam L1 incident from the light source 2 to the field of view area set for the user's eye. In other words, the optical system 3 is configured to relay the pupil of the light beam L1 from the light source 2 to the user's eye.

[0017] The optical system 3 comprises a deflection unit 4, an optical element 5, and a light guide member 6. In the optical system 3, the light beam L1 from the light source 2 is incident on the deflection unit 4.

[0018] The deflection unit 4 dynamically deflects the incident light beam L1. The light beam L1 deflected by the deflection unit 4 is incident on the optical element 5 as a light beam L2. In this embodiment, "dynamically deflected" means that the direction in which the light beam L1 incident on the deflection unit 4 exits the deflection unit 4 can be changed. The deflection unit 4 scans the incident light beam L1 in two dimensions. As a result, the deflection unit 4 can form an image with the light beam L1 from the light source 2. The deflection unit 4 is a reflective deflection element. An example of a reflective deflection element is a scanning MEMS mirror. In this embodiment, the deflection unit 4 is a two-axis MEMS mirror. As shown in Figures 2 and 3, the deflection unit 4 may include one or more reflectors 41 that can rotate around one or more rotation axes. In this embodiment, the deflection unit 4 includes one reflector 41 that can rotate around two rotation axes. The deflection unit 4 is capable of deflecting the light beam L1 along the first axis A1 and the second axis A2, which intersect with each other. In this embodiment, the first axis A1 and the second axis A2 are orthogonal to each other. The first axis A1 and the second axis A2 will be described in detail later.

[0019] Refer to Figure 1 again. The optical element 5 focuses the light beam L2 incident from the deflection unit 4. The optical element 5 has a plurality of unit optical elements 51. Each unit optical element 51 includes an incident part 511 into which the light beam L2 from the deflection unit 4 is incident, a reflecting part 512 that reflects the light beam L2 incident from the incident part 511, and an exit part 513 that emits the light beam L2 reflected by the reflecting part 512 (as a light beam L3). In each of the plurality of unit optical elements 51, the reflecting part 512 has two reflecting surfaces 512a, 512b that reflect the light beam L2 incident from the incident part 511 an even number of times so that the light beam L3 from the exit part 513 is directed toward a focusing position P that is plane-symmetric with respect to the deflection unit 4 with respect to a virtual plane S between the incident part 511 of the plurality of unit optical elements 51 and the exit part 513 of the plurality of unit optical elements 51. In this way, the optical element 5 focuses the light beam L2 from the deflection section 4 to the focusing position P by reflecting it an even number of times using the unit optical element 51. The optical element 5 will be described in more detail below.

[0020] Figure 4 is a schematic perspective view of the optical element 5. The optical element 5 comprises a plurality of unit optical elements 51 and a main body 52.

[0021] The main body portion 52 is formed of a light-transmitting material. Preferably, the light-transmitting material is a material that is transparent in the visible light region. The main body portion 52 is plate-shaped. In this embodiment, the main body portion 52 is a rectangular plate. The main body portion 52 has a first surface 52a and a second surface 52b in the thickness direction of the main body portion 52. For example, the main body portion 52 is positioned with the first surface 52a facing the deflection portion 4 side and the second surface 52b facing the light guide member 6 side.

[0022] Each of the multiple unit optical elements 51 is defined by a protrusion of a light-transmitting material formed on the main body 52. ​​The light-transmitting material is preferably a material that is transparent in the visible light region. The multiple unit optical elements 51 have the same shape. In this embodiment, the multiple unit optical elements 51 are arranged on the first surface 52a of the main body 52. ​​The multiple unit optical elements 51 are arranged in a two-dimensional array at predetermined intervals on the first surface 52a of the main body 52. ​​In other words, the optical element 5 has an array of multiple unit optical elements 51. The optical element 5 functions as a so-called two-sided corner reflector array.

[0023] Figure 5 is a schematic perspective view of a unit optical element 51. In each unit optical element 51, both sides in the longitudinal direction of the protrusion (the upper and lower surfaces in Figure 5) define the incident portion 511 and the outgoing portion 513, and the outer surface of the protrusion defines the reflective portion 512 (two reflective surfaces 512a and 512b). Although the entire outer surface of the protrusion can function as a reflective portion 512, which part of the outer surface actually functions as a reflective portion can be appropriately adjusted by the arrangement of the optical element 5 with respect to the deflection portion 4.

[0024] In this embodiment, the incident portion 511 is the interface between the main body portion 52 and the unit optical element 51. When the unit optical element 51 is integrally formed with the main body portion 52, the incident portion 511 becomes a virtual surface. In the optical element 5, the virtual surface S is a virtual surface between the incident portions 511 of the multiple unit optical elements 51 and the emission portions 513 of the multiple unit optical elements 51. In this embodiment, the incident portions 511 of the multiple unit optical elements 51 are on the same first plane (first surface 52a), and the emission portions 513 of the multiple unit optical elements 51 are on the same second plane. The first plane (first surface 52a), the second plane, and the virtual surface S are parallel to each other.

[0025] The two reflective surfaces 512a and 512b are adjacent to each other on the outer surface of the protrusion. In this embodiment, the unit optical element 51 is square in shape when viewed from above, and the two reflective surfaces 512a and 512b are orthogonal to each other.

[0026] Multiple unit optical elements 51 do not need to be arranged across the entire surface of the first surface 52a of the main body 52, but may be arranged wherever necessary.

[0027] The inventors of this application have diligently investigated the arrangement of the unit optical elements 51 and have found the following:

[0028] The deflection unit 4 is capable of dynamically deflecting the light beam L1 along the first axis A1. Here, as can be understood from Figures 1 and 2, the first axis A1 is the axis in which the deflection unit 4 and the reference position P0 of the deflection of the light beam L1 by the deflection unit 4 in the optical element 5 are aligned when viewed from the normal direction of the virtual plane S of the optical element 5. The reference position P0 is the position where the light beam L2-1, which corresponds to the center of the deflection by the deflection unit 4, is incident on the optical element 5. The minimum angle of the light beam L2 from the deflection unit 4 with respect to the first axis A1 (the angle of the light beam L2-2 in Figure 2) is θ. ymin [°] The maximum angle of the luminous beam L2 from the deflection unit 4 with respect to the first axis A1 (angle of the luminous beam L2-3 in Figure 2) is θ ymaxLet the angle be [°], and let h be the distance between the deflection part 4 and the optical element 5 in the direction normal to the virtual plane S. At least some of the multiple unit optical elements 51 have a distance of h / tanθ from the deflection part 4 in the direction of the first axis A1 in the optical element 5. ymax or more h / tanθ ymin It is preferable that the luminous flux L2 is within the following range. This makes it possible to improve the utilization efficiency of the luminous flux L2.

[0029] The deflection unit 4 is capable of dynamically deflecting the luminous beam L1 along the second axis A2. Here, as can be understood from Figures 1 and 3, the second axis A2 is an axis perpendicular to the first axis A1 when viewed from the normal direction of the virtual plane S. The maximum angle of the luminous beam L2 in the first direction (leftward direction in Figure 3) from the deflection unit 4 along the second axis A2 relative to the first axis A1 (angle of luminous beam L2-4 in Figure 3) is θ xl [°] The maximum angle of the luminous beam L2 in the second direction (left direction in Figure 3) opposite to the first direction along the second axis A2 from the deflection part 4 relative to the first axis A1 (angle of luminous beam L2-5 in Figure 3) is θ xr Let [°] be the angle, and let L be the distance between the deflection portion 4 and the reference position P0 as viewed from the normal direction of the virtual plane S. At least some of the multiple unit optical elements 51 have a distance of Ltanθ from the reference position P0 in the first direction in the optical element 5. xl Below, the distance from the reference position P0 in the second direction is Ltanθ. xr It is preferable that the luminous flux L2 is within the following range. This makes it possible to improve the utilization efficiency of the luminous flux L2.

[0030] Figure 6 is an explanatory diagram of the arrangement of the unit optical elements 51. In Figure 6, simply to simplify the diagram, four unit optical elements 51 (51-1 to 51-4) are shown, and for each unit optical element 51, only the reflective portion 512 (reflective surfaces 512a, 512b) is shown. Also, to simplify the explanation, adjacent reflective portions 512 are drawn connected to each other.

[0031] In the present embodiment, the spacing between the unit optical elements 51 is determined in consideration of the beam width of the light beam L2 incident on the optical element 5 from the deflecting unit 4. The beam width of the light beam L2 may be defined as the distance between two points at which the radiation intensity is 1 / 2 of the peak radiation intensity (that is, the full width at half maximum). Note that the beam width is 1 / e of the radiation intensity with respect to the peak radiation intensity 2 It may also be defined as the distance between two points where . Let c be the spacing between the plurality of unit optical elements 51, and d be the beam width of the light beam L2 from the deflecting unit 4, then d≧2c is satisfied. This makes it possible to increase the probability that light rays included in the light beam L2 are reflected an even number of times by the optical element 5, which improves the utilization efficiency of the light beam L2, and improves the uniformity of the light intensity distribution of an image formed by the deflecting unit 4 in the viewing field area.

[0032] In the present embodiment, the plurality of unit optical elements 51 are arranged such that the two outermost rays L2a and L2b that define the beam width d of the light beam L2 from the deflecting unit 4 are each reflected an even number of times by the reflecting portions 512 of different unit optical elements 51-1 and 51-4 among the plurality of unit optical elements 51.

[0033] In the example shown in Figure 6, the light ray L2a is reflected by the reflective surfaces 512a and 512b of the reflecting part 512 of the unit optical element 51-1 in that order, and is emitted from the optical element 5 as the light ray L3a. In the light beam L2, the light ray L2c, which is inside the light ray L2a, is reflected by the reflective surfaces 512b and 512a of the reflecting part 512 of the unit optical element 51-1 in that order, and is emitted from the optical element 5 as the light ray L3c. Here, the light ray L3c is located outside the light ray L3a. The light ray L2b is reflected by the reflective surfaces 512b and 512a of the reflecting part 512 of the unit optical element 51-4 in that order, and is emitted from the optical element 5 as the light ray L3b. In the luminous beam L2, the ray L2d, which is inside the ray L2b, is reflected in order by the reflective surfaces 512a and 512b of the reflecting part 512 of the unit optical element 51-1, and is emitted from the optical element 5 as ray L3d. Here, ray L3d is located outside the ray L3b. In other words, the rays L3a and L3d that originate from the rays L2c and L2d, which are inside the rays L2a and L2b, rather than the rays L3a and L3b that originate from the rays L2a and L2b that define the beam width d of the luminous beam L2 from the deflection part 4, can become the rays at the outer edges that define the beam width e of the luminous beam L3 from the optical element 5. As a result, the beam width e of the luminous beam L3 from the optical element 5 becomes wider than the beam width d of the luminous beam L2 from the deflection part 4. This makes it possible for the optical element 5 to expand the pupil of the luminous beam L1.

[0034] Next, the size of the unit optical element 51 will be further explained. Figures 7 to 9 are explanatory diagrams of the optical path in the unit optical element 51. In Figures 7 to 9, the relationship between the size a of the incident portion 511 and the outgoing portion 513 of the unit optical element 51 and the distance t between the incident portion 511 and the outgoing portion 513 is different. In this embodiment, the unit optical element 51 is a square-shaped projection in plan view. The size a of the incident portion 511 and the outgoing portion 513 corresponds to the length of one side of the projection in plan view. The distance t between the incident portion 511 and the outgoing portion 513 corresponds to the height of the projection.

[0035] Comparing Figures 7 to 9, the distance t between the inlet section 511 and the outlet section 513 is shortest in Figure 7 and longest in Figure 9.

[0036] As shown in Figure 7, when the distance t is short, the amount of light beam L3 reflected by the reflecting part 512 of the unit optical element 51 and directed toward the focusing position P decreases, and the amount of light beam L4 passing through the unit optical element 51 without being reflected by the reflecting part 512 increases. This can be one of the causes of a decrease in the utilization efficiency of light beam L2. Conversely, as shown in Figure 8, when the distance t is longer than in Figure 7, the amount of light beam L4 passing through the unit optical element 51 without being reflected by the reflecting part 512 decreases, and the amount of light beam L3 reflected by the reflecting part 512 and directed toward the focusing position P increases. However, as shown in Figure 9, when the distance t becomes too long, the amount of light beam L5 that becomes stray light after being reflected by the reflecting part 512 and not reaching the output part 513 increases, and as a result, the amount of light beam L3 reflected by the reflecting part 512 and directed toward the focusing position P decreases. This can be one of the causes of a decrease in the utilization efficiency of light beam L2.

[0037] The inventors of this application have diligently investigated the relationship between the size a of the incident portion 511 and the outgoing portion 513 of the unit optical element 51 and the distance t between the incident portion 511 and the outgoing portion 513, and have found the following:

[0038] In each of the multiple unit optical elements 51, the refractive index is n, the size of the incident portion 511 and the outgoing portion 513 is a, the distance between the incident portion 511 and the outgoing portion 513 is t, and the maximum incident angle of the light beam L2 from the deflection portion 4 is θ. max If the temperature is [°], it is preferable that the following equation (1) is satisfied. This makes it possible to improve the utilization efficiency of the luminous flux L2.

[0039]

number

[0040] In each of the multiple unit optical elements 51, the minimum incident angle of the light beam L2 from the deflection section 4 is set to θ. min If [°], it is preferable that the following equation (2) is also satisfied. This makes it possible to further improve the utilization efficiency of the luminous flux L2.

[0041]

number

[0042] Let's consider the case where the incident angle of the light beam L2 from the deflection unit 4 is in the range of 25° to 80°. For simplicity, the following equation (3) can be used.

[0043]

number

[0044] Furthermore, the light-transmitting material used for the unit optical element 51 generally has a refractive index of approximately 1.4 to 1.6. For simplicity, the following equation (4) can be used.

[0045]

number

[0046] Refer to Figure 1 again. The light guide member 6 is located at the focusing position P of the optical element 5 and propagates the light beam L3 from the optical element 5. This allows the pupil of the light beam L3 (the pupil of the light beam L1) to be positioned at the desired location. In particular, in this embodiment, the light guide member 6 is used to widen the field of view through the action of the exit pupil expansion optical system.

[0047] Figure 10 is a schematic perspective view of the light guide member 6. The light guide member 6 comprises a main body portion 60, a coupling region 61, a first replication region 62, and a second replication region 63.

[0048] The main body 60 is made of a material that is transparent in the visible light region. The main body 60 is plate-shaped. In this embodiment, the main body 60 is rectangular plate-shaped. The main body 60 has a first surface 60a and a second surface 60b in the thickness direction of the main body 60. As shown in Figure 1, the main body 60 is positioned with the first surface 60a facing the optical element 5 side and the second surface 60b facing the field of view region side.

[0049] The coupling region 61 is formed in the main body portion 60. The light beam L3 from the optical element 5 is incident into the main body portion 60 so that it propagates within the main body portion 60. In this embodiment, the light guide member 6 is arranged such that the coupling region 61 is at the focusing position P. The coupling region 61 causes the light beam L3 to propagate within the main body portion 60 in a first propagation direction (X direction in Figure 10) perpendicular to the thickness direction of the main body portion 60. The coupling region 61 is used for coupling between the optical element 5 and the light guide member 6. The coupling region 61 causes the light beam L3 to propagate within the main body portion 60 under total internal reflection conditions. "Coupling" here refers to the state in which light propagates within the main body portion 60 of the light guide member 6 under total internal reflection conditions.

[0050] The coupling region 61 is composed of a periodic structure that has a diffracting effect on the light beam L3. The periodic structure of the coupling region 61 is, for example, a surface relief type diffraction grating. The periodic structure of the coupling region 61 may include, for example, a plurality of recesses or protrusions that extend in a specified direction (for example, the Y direction in Figure 10) perpendicular to the thickness direction of the main body 60 and intersecting the first propagation direction, and are arranged at predetermined intervals in the first propagation direction. The coupling region 61 causes the light beam L3 to be incident into the main body 60 under conditions of total internal reflection by the first surface 60a and the second surface 60b. Due to the coupling region 61, the light beam L3 is totally reflected by the first surface 60a and the second surface 60b and becomes a light beam L6 that propagates within the main body 60 in the first propagation direction.

[0051] The first replication region 62 is formed in the main body 60. The first replication region 62 divides the light beam L6 propagating in a first propagation direction intersecting the thickness direction of the main body 60 into a plurality of light beams L7 propagating in a second propagation direction intersecting the first propagation direction (for example, the Y direction in Figure 10). By dividing the light beam L6, the first replication region 62 directs the plurality of light beams L7 toward the second replication region 63. In this way, the first replication region 62 replicates and expands the pupil of the light beam L1 from the light source 2 in the first propagation direction.

[0052] The first replication region 62 is composed of a periodic structure having a diffracting effect on the light beam L6. The periodic structure of the first replication region 62 is, for example, a surface relief type diffraction grating. As an example, the periodic structure of the first replication region 62 is composed of uneven surfaces in the thickness direction of the main body 60, which are arranged to have periodicity in the periodic direction. The periodic direction is the direction in which the uneven surfaces are arranged to have periodicity. As an example, the periodic direction of the periodic structure of the first replication region 62 may be a direction inclined at 20° to 70° with respect to the first propagation direction in a plane perpendicular to the thickness direction of the main body 60.

[0053] The second replication region 63 is formed in the main body 60. The second replication region 63 divides the multiple luminous beams L7 propagating in the second propagation direction from the first replication region 62 into multiple luminous beams L8 that are aligned in the second propagation direction and propagate in the direction of the field of view (Z direction in Figure 10). By dividing the luminous beams L7, the second replication region 63 directs the multiple luminous beams L8 aligned in the second propagation direction toward the field of view. In this way, the second replication region 63 replicates and expands the pupil of the luminous beam L1 from the light source 2 in the second propagation direction.

[0054] The second replication region 63 is composed of a periodic structure having a diffracting effect on the light beam L7. The periodic structure of the second replication region 63 is, for example, a surface relief type diffraction grating. As an example, the periodic structure of the second replication region 63 has periodicity in the second propagation direction. The periodic structure of the second replication region 63 may include, for example, a plurality of recesses or protrusions that extend in the first propagation direction and are arranged at predetermined intervals in the second propagation direction in a plane perpendicular to the thickness direction of the main body 60.

[0055] In this way, the light guide member 6 divides the light beam L3 that enters the main body portion 60 of the light guide member 6 from the coupling region 61 into a plurality of light beams L7 that are aligned in the first propagation direction and propagate in the second propagation direction within the main body portion 60, and further divides each light beam L7 into a plurality of light beams L8 that are aligned in the second propagation direction and head toward the field of view, thereby replicating and expanding the pupil of the light beam L1 in both the first and second propagation directions.

[0056] In the optical system 3 described above, the light beam L1 from the light source 2 is dynamically deflected by the deflection unit 4. The light beam L2, dynamically deflected by the deflection unit 4, is converted into a light beam L3 that is focused at the focusing position P by the optical element 5, and the light beam L3 is propagated into the field of view by the light guide member 6. The light beam L2, dynamically deflected by the deflection unit 4, can be focused by the optical element 5, which is a single component. Therefore, it is not necessary to combine and arrange multiple optical components in order to focus the light beam L2, which is dynamically deflected by the deflection unit 4. As a result, the optical system 3 can be miniaturized. In addition, since the relatively difficult task of combining and arranging multiple optical components is not required, the time and cost required for manufacturing the optical system 3 can be reduced, and the mass production capability of the optical system 3 is improved.

[0057] [1.1.2 Effects, etc.] The optical system 3 described above comprises a deflection unit 4 that dynamically deflects an incident light beam L1, and an optical element 5 having a plurality of unit optical elements 51. Each of the plurality of unit optical elements 51 includes an incident part 511 into which the light beam L2 from the deflection unit 4 is incident, a reflecting part 512 that reflects the light beam L2 incident from the incident part 511, and an outgoing part 513 that emits the light beam L3 reflected by the reflecting part 512. In each of the plurality of unit optical elements 51, the reflecting part 512 has two or more reflective surfaces 512a, 512b that reflect the light beam L2 incident from the incident part 511 an even number of times, such that the light beam L3 from the outgoing part 513 is directed toward a focusing position P that is plane-symmetric with respect to the deflection unit 4 with respect to a virtual plane S between the incident part 511 of the plurality of unit optical elements 51 and the outgoing part 513 of the plurality of unit optical elements 51. This configuration enables miniaturization and improved mass production.

[0058] In the optical system 3, the multiple unit optical elements 51 are arranged such that the light rays L2a and L2b at both outer edges that define the beam width d of the light beam L2 from the deflection unit 4 are reflected an even number of times by the reflecting parts 512 of different unit optical elements 51-1 and 51-4 among the multiple unit optical elements 51. This configuration allows the pupil of the light beam L1 to be expanded by the optical element 5.

[0059] In the optical system 3, the deflection unit 4 includes one or more reflecting mirrors 41 that can rotate around one or more rotation axes. This configuration enables miniaturization.

[0060] In the optical system 3, the deflection unit 4 scans the incident light beam L1 in two dimensions. This configuration enables the formation of an image.

[0061] In optical system 3, the light beam L3 from optical element 5 is approximately collimated light. This configuration enables improved utilization efficiency of the light beam L1.

[0062] The optical system 3 is located at the focusing position P and includes a light guide member 6 that propagates the light beam L3 from the optical element 5. This configuration allows the pupil of the light beam L1 to be positioned at a desired location.

[0063] In the optical system 3, two or more reflective surfaces 512a, 512b include two mutually orthogonal reflective surfaces 512a, 512b. This configuration enables miniaturization and improved mass production.

[0064] In the optical system 3, the optical element 5 comprises a plate-shaped main body 52, and each of the multiple unit optical elements 51 is defined by a projection of a light-transmitting material formed on the main body 52. ​​Both sides of the projection in the longitudinal direction define an incident portion 511 and an outgoing portion 513, and the outer surface of the projection defines two reflective surfaces 512a and 512b. This configuration enables miniaturization and improved mass production.

[0065] In the optical system 3, in each of the multiple unit optical elements 51, the refractive index is n, the size of the incident part 511 and the outgoing part 513 is a, the distance between the incident part 511 and the outgoing part 513 is t, and the maximum incident angle of the light beam L2 from the deflection part 4 is θ. max If we set it to [°], then equation (1) is satisfied. This configuration enables improved utilization efficiency of the luminous flux L2.

[0066]

number

[0067] In the optical system 3, the minimum incident angle of the light beam L2 from the deflection section 4 is set to θ in each of the multiple unit optical elements 51. min If we set it to [°], then equation (2) is satisfied. This configuration enables improved utilization efficiency of the luminous flux L2.

[0068]

number

[0069] In the optical system 3, if the refractive index of each of the multiple unit optical elements 51 is n, the size of the incident part 511 and the exit part 513 is a, and the distance between the incident part 511 and the exit part 513 is t, then the following equation (3) is satisfied.

[0070]

number

[0071] In the optical system 3, if the size of the incident portion 511 and the outgoing portion 513 of each of the multiple unit optical elements 51 is a, and the distance between the incident portion 511 and the outgoing portion 513 is t, then the following equation (4) is satisfied. This configuration enables an improvement in the utilization efficiency of the light beam L2.

[0072]

number

[0073] In the optical system 3, if c is the distance between the multiple unit optical elements 51 and d is the beam width of the light beam L2 from the deflection unit 4, then d ≥ 2c is satisfied. This configuration enables improved utilization efficiency of the light beam L2.

[0074] In the optical system 3, the deflection unit 4 dynamically deflects the incident light beam L1 along the first axis A1, where the deflection unit 4 and the reference position P0 of the deflection of the light beam L2 by the deflection unit 4 in the optical element 5 are aligned when viewed from the normal direction of the virtual plane S. The minimum angle of the light beam L2 from the deflection unit 4 with respect to the first axis A1 is θ ymin [°], the maximum angle of the light beam L2 from the deflection unit 4 with respect to the first axis A1 is θymax [°] If the distance between the deflection part 4 and the optical element 5 in the direction normal to the virtual plane S is h, then at least some of the multiple unit optical elements 51 have a distance of h / tanθ from the deflection part 4 in the direction of the first axis A1 in the optical element 5. ymax or more h / tanθ ymin It falls within the following range. This configuration allows for improved utilization efficiency of luminous flux L2.

[0075] In the optical system 3, the deflection unit 4 dynamically deflects the incident light beam L2 along a second axis A2 that is perpendicular to the first axis A1, where the deflection unit 4 and the reference position P0 of the deflection of the light beam L2 by the deflection unit 4 in the optical element 5 are aligned when viewed from the normal direction of the virtual plane S. The maximum angle of the light beam L2 in the first direction from the deflection unit 4 along the second axis A2 with respect to the first axis A1 is θ xl [°], the maximum angle of the luminous beam L2 in the second direction opposite to the first direction along the second axis A2 from the deflection unit 4 with respect to the first axis A1 is θ r [°], if L is the distance between the deflection part 4 and the reference position P0 as viewed from the normal direction of the virtual plane S, then at least some of the multiple unit optical elements 51 are such that in the optical element 5, the distance from the reference position P0 in the first direction is Ltanθ l Below, the distance from the reference position P0 in the second direction is Ltanθ. r It falls within the following range. This configuration allows for improved utilization efficiency of luminous flux L2.

[0076] [1.2 Embodiment 2] [1.2.1 Structure] Figure 11 is a schematic perspective view of an image display device 1A equipped with an optical system 3A according to this embodiment. Figure 12 is a side view of the image display device 1A.

[0077] The optical system 3A comprises a plurality of deflection units 4 (first deflection unit 4a and second deflection unit 4b), a plurality of optical elements 5 (first optical element 5a and second optical element 5b), and a light guide member 6. In the optical system 3A, the light beam L1 from the light source 2 is incident on the first deflection unit 4a.

[0078] The first deflection unit 4a dynamically deflects the incident light beam (light beam L1 incident from the light source 2). The light beam L1 deflected by the first deflection unit 4a is incident on the first optical element 5a as light beam L21. The first deflection unit 4a scans the incident light beam L1 in one dimension. The first deflection unit 4a may be, for example, a scanning MEMS mirror. In this embodiment, the first deflection unit 4a is a uniaxial MEMS mirror. The first deflection unit 4a includes one reflecting mirror 41 that is rotatable about one axis of rotation. The first deflection unit 4a is capable of deflecting the light beam L1 on a second axis A2.

[0079] The first optical element 5a focuses the light beam L21 incident from the first deflection section 4a. Similar to the optical element 5, the first optical element 5a has a main body 52 and a plurality of unit optical elements 51 (hereinafter referred to as the first unit optical element 51a). The first optical element 5a reflects the light beam L21 incident from the incident section 511 even number of times so that the light beam L31 from the emission section 513 of the first unit optical element 51a is directed toward a first focusing position Pa that is plane-symmetric with respect to the first deflection section 4a with respect to a first virtual plane Sa between the incident section 511 of the plurality of first unit optical elements 51a and the emission section 513 of the plurality of first unit optical elements 51a. In other words, the first optical element 5a focuses the light beam L21 from the first deflection section 4a toward the first focusing position Pa by reflecting it even number of times with the first unit optical elements 51a.

[0080] In this embodiment, the first deflection unit 4a is capable of dynamically deflecting the light beam L21 along the second axis A2. Here, the explanation relating to Figure 3 can be applied by substituting the deflection unit 4 with the first deflection unit 4a, the optical element 5 with the first optical element 5a, etc. Therefore, at least a portion of the plurality of first unit optical elements 51a have a distance of Ltanθ from the reference position P0 in the first direction in the first optical element 5a. xl Below, the distance from the reference position P0 in the second direction is Ltanθ. xr It is preferable that the luminous flux L21 is within the following range. This makes it possible to improve the utilization efficiency of the luminous flux L21.

[0081] The second deflection unit 4b is located at the first focusing position Pa and dynamically deflects the incident light beam (light beam L31 incident from the first optical element 5a). The light beam L31 deflected by the second deflection unit 4b is incident on the second optical element 5b as light beam L22. The second deflection unit 4b scans the incident light beam L31 in one dimension. The second deflection unit 4b may be, for example, a scanning MEMS mirror. In this embodiment, the second deflection unit 4b is a uniaxial MEMS mirror. The second deflection unit 4b includes one reflecting mirror 41 that is rotatable about one axis of rotation. The second deflection unit 4b is capable of deflecting the light beam L31 on the first axis A1. In this embodiment, the first deflection unit 4a and the second deflection unit 4b scan the incident light beams L1 and L31 in directions that intersect each other. As a result, the first deflection unit 4a and the second deflection unit 4b work together to form an image using the light beam L1 from the light source 2.

[0082] The second optical element 5b focuses the light beam L22 incident from the second deflection section 4b. Similar to the optical element 5, the second optical element 5b has a main body 52 and a plurality of unit optical elements 51 (hereinafter referred to as the second unit optical element 51b). The second optical element 5b reflects the light beam L22 incident from the incident part 511 even number of times so that the light beam L32 from the emission part 513 of the second unit optical element 51b is directed toward the second focusing position Pb, which is symmetrical with respect to the second deflection section 4b with respect to the second virtual plane Sb between the incident part 511 of the plurality of second unit optical elements 51b and the emission part 513 of the plurality of second unit optical elements 51b. In other words, the second optical element 5b focuses the light beam L22 from the second deflection section 4b toward the second focusing position Pb by reflecting it even number of times with the second unit optical elements 51b.

[0083] In this embodiment, the second deflection unit 4b is capable of dynamically deflecting the luminous beam L22 along the first axis A1. As shown in Figure 12, the minimum angle of the luminous beam L22 from the second deflection unit 4b with respect to the first axis A1 is θ ymin [°], the maximum angle of the luminous beam L22 from the second deflection unit 4b with respect to the first axis A1 is θ ymaxLet the angle be [°], and let h be the distance between the second deflection section 4b and the second optical element 5b in the direction normal to the second virtual plane Sb. At least some of the multiple second unit optical elements 51b have a distance of h / tanθ from the second deflection section 4b in the direction of the first axis A1. ymax or more h / tanθ ymin It is preferable that the range be as follows. This will allow for an improvement in the utilization efficiency of the luminous flux L22.

[0084] The light guide member 6 is located at the second focusing position Pb of the second optical element 5b and propagates the light beam L32 from the second optical element 5b. This allows the pupil of the light beam L32 (the pupil of the light beam L1) to be positioned at a desired location. The light guide member 6 is used to widen the field of view through the action of the exit pupil expansion optical system.

[0085] In the optical system 3A, the first virtual plane Sa of the first optical element 5a and the second virtual plane Sb of the second optical element 5b are parallel to each other. The first deflection section 4a is on the opposite side of the second deflection section 4b from the second optical element 5b.

[0086] [1.1.2 Effects, etc.] In the optical system 3A described above, the deflection section 4 includes a first deflection section 4a and a second deflection section 4b, and the optical element 5 includes a first optical element 5a to which a light beam L21 from the first deflection section 4a is incident, and a second optical element 5b to which a light beam L22 from the second deflection section 4b is incident. The plurality of unit optical elements 51 includes a plurality of first unit optical elements 51a in the first optical element 5a and a plurality of second unit optical elements 51b in the second optical element 5b. In each of the plurality of first unit optical elements 51a, the reflection section 512 directs the light beam L31 from the emission section 513 toward a first focusing position Pa that is plane-symmetric with respect to the first deflection section 4a with respect to a first virtual plane Sa between the incidence section 511 of the plurality of first unit optical elements 51a and the emission section 513 of the plurality of first unit optical elements 51a. The second deflection unit 4b is located at the first focusing position Pa and dynamically deflects the light beam L31 incident from the first optical element 5a. In each of the multiple second unit optical elements 51b, the reflecting unit 512 directs the light beam L32 from the emission unit 513 toward a second focusing position Pb that is plane-symmetric with respect to the second deflection unit 4b with respect to a second virtual plane Sb between the incidence unit 511 and the emission unit 513 of the multiple second unit optical elements 51b. This configuration enables miniaturization and improved mass production.

[0087] In the optical system 3A, the first deflection unit 4a and the second deflection unit 4b scan the incident light beam in directions that intersect each other. This configuration enables the formation of an image.

[0088] [2. Variant] The embodiments of this disclosure are not limited to those described above. The embodiments can be modified in various ways depending on the design, etc., as long as the objectives of this disclosure can be achieved. The following lists some modifications of the embodiments. The modifications described below can be combined and applied as appropriate.

[0089] In the following, even if the reference numerals used in Embodiment 1 are applicable to either Embodiment 1 or 2 described above, we will refer to them only if they were used in Embodiment 1. This is simply for the purpose of simplifying the description and is not intended to exclude their application to Embodiment 2.

[0090] In one modified example, the positional relationship between the deflection unit 4 and the optical element 5 may be changed as appropriate, for example, depending on the application of the image display device 1. Figure 13 is a side view of the optical system 3B according to one modified example. Similar to the optical system 3A, the optical system 3B comprises a plurality of deflection units 4 (first deflection unit 4a and second deflection unit 4b), a plurality of optical elements (first optical element 5a and second optical element 5b), and a light guide member 6. In the optical system 3B, the first virtual plane Sa of the first optical element 5a and the second virtual plane Sb of the second optical element 5b are orthogonal to each other. The first deflection unit 4a is on the same side as the second optical element 5b with respect to the second deflection unit 4b. Similarly, the relationship between the first virtual plane Sa of the first optical element 5a and the second virtual plane Sb of the second optical element 5b may be changed as appropriate.

[0091] In one modified example, the positional relationship between the optical element 5 and the light guide member 6 may be appropriately changed depending on the application of the image display device 1, for example. By increasing the angle of the virtual plane S of the optical element 5 with respect to the light guide member 6 (for example, the first surface 60a of the main body of the light guide member 6), the angle of incidence of the light beam from the deflection unit 4 to the optical element 5 can be increased. When the angle of incidence of the light beam from the deflection unit 4 increases, the upper limit of the distance t between the incident unit 511 and the output unit 513 decreases from equation (1) above. Therefore, the thickness of the optical element 5 can be reduced. This makes it possible to lighten the optical element 5. On the other hand, by decreasing the angle of the virtual plane S of the optical element 5 with respect to the first surface 60a) of the main body of the light guide member 6, the dimensions of the image display device 1 in the thickness direction of the first surface 60a) of the main body of the light guide member 6, that is, the thickness of the image display device 1 can be reduced.

[0092] In one modified example, the number of deflection units 4 and optical elements 5 is not particularly limited.

[0093] In one modified example, the deflection unit 4 is not limited to a reflective deflection element, but may be a transmissive deflection element. Examples of transmissive deflection elements include acousto-optic elements (AOD, AOM, etc.) or liquid crystal lenses.

[0094] In one modified example, the unit optical element 51 of the optical element 5 is not limited to a protrusion. Figure 14 is a schematic perspective view of the optical element 5C according to one modified example. The optical element 5C comprises a plurality of unit optical elements 51C and a main body 52. ​​Each of the plurality of unit optical elements 51C is defined by a through hole formed in the main body 52. ​​The plurality of unit optical elements 51 have the same shape. In this embodiment, the plurality of unit optical elements 51C extend from the first surface 52a to the second surface 52b of the main body 52. ​​The plurality of unit optical elements 51C are arranged in a two-dimensional array at predetermined intervals on the first surface 52a of the main body 52. ​​In other words, the optical element 5C has an array of the plurality of unit optical elements 51C. The optical element 5C functions as a so-called two-sided corner reflector array. Figure 15 is a schematic perspective view of the unit optical element 51C. In each unit optical element 51C, both openings of the through-hole (the upper and lower openings in Figure 15) define the incident portion 511 and the exit portion 513, and the inner surface of the through-hole defines the reflective portion 512 (two reflective surfaces 512a and 512b). While the entire inner surface of the through-hole can function as the reflective portion 512, the specific portion of the inner surface that functions as the reflective portion 512 can be adjusted as appropriate by the arrangement of the optical element 5C relative to the deflection portion 4. The two reflective surfaces 512a and 512b are adjacent surfaces on the inner surface of the through-hole. In Figure 15, the unit optical element 51C is square in plan view, and the two reflective surfaces 512a and 512b are orthogonal to each other. This configuration enables miniaturization and improved mass production.

[0095] In one modified example, the optical system 3 may include a projection optical system such that the light beam L3 from the optical element 5 becomes substantially collimated light. The projection optical system may consist of one or more optical components. Various lenses or prisms can be used as optical components.

[0096] In one modified example, the light source 2 and the deflection unit 4 in the optical system 3 do not necessarily have to be aligned in a straight line. In other words, the optical path of the light beam L1 is not necessarily straight. For example, the light beam L1 from the light source L1 may be reflected by a reflector and incident on the deflection unit 4. In this case, the optical path of the light beam L1 from the light source 2 to the deflection unit 4 is not straight, but for example, L-shaped. This point is also true for the relationship between the deflection unit 4 and the optical element 5, the relationship between the optical element 5 and the light guide member 6, and the relationship between the light guide member 6 and the field of view.

[0097] In one modified example, each periodic structure of the light guide member 6 is not limited to a surface relief type diffraction grating, but may have a volume hologram element (holographic diffraction grating) or a half mirror.

[0098] In one modified example, the image display device 1 may be equipped with a plurality of light guide members 6, each corresponding to a wavelength of light contained in the light beam L1 from the light source 2. This can reduce the effects of aberrations in the light contained in the light beam L1.

[0099] In one modified example, the light guide member 6 does not necessarily have to have a function of dilating the pupil. The light guide member 6 may be, for example, an optical fiber, a prism, or the like that propagates the light beam to a predetermined position.

[0100] In one modified example, the image display device 1 does not necessarily have to include the light guide member 6.

[0101] In one modified example, the image display device 1 is not necessarily limited to an HMD, but may be a head-up display (HUD), a projector, or the like.

[0102] [3. Appearance] As will be apparent from the above embodiments and modifications, this disclosure includes the following aspects.

[0103] [Aspect 1] A deflection unit that dynamically deflects the incident light beam, An optical element having multiple unit optical elements, Equipped with, Each of the aforementioned plurality of unit optical elements is The incident portion into which the light beam from the deflection portion is incident, A reflecting part that reflects the light beam incident from the aforementioned incident part, A emitting section that emits the light beam reflected by the aforementioned reflective section, Includes, In each of the plurality of unit optical elements, the reflecting portion has two or more reflecting surfaces that reflect the light beam incident from the incident portion an even number of times, such that the light beam from the exit portion is directed toward a focusing position that is plane-symmetric with respect to the deflection portion with respect to a virtual plane between the incident portion of the plurality of unit optical elements and the exit portion of the plurality of unit optical elements. optical system.

[0104] [Aspect 2] The deflection unit includes a first deflection unit and a second deflection unit. The optical element includes a first optical element to which a light beam from the first deflection unit is incident, and a second optical element to which a light beam from the second deflection unit is incident. The plurality of unit optical elements include a plurality of first unit optical elements in the first optical element and a plurality of second unit optical elements in the second optical element. In each of the plurality of first unit optical elements, the reflecting portion directs the light beam from the emitting portion toward a first focusing position that is plane-symmetric with the first deflecting portion with respect to a first virtual plane between the incident portion and the emitting portion of the plurality of first unit optical elements. The second deflection unit is located at the first light-gathering position and dynamically deflects the light beam incident from the first optical element. In each of the plurality of second unit optical elements, the reflecting portion directs the light beam from the emitting portion toward a second focusing position that is symmetrical with the second deflecting portion with respect to a second virtual plane between the incident portion and the emitting portion of the plurality of second unit optical elements. Optical system of embodiment 1.

[0105] [Aspect 3] The plurality of unit optical elements are arranged such that the rays from both outer edges that define the beam width of the light beam from the deflection portion are reflected an even number of times by the reflecting portions of different unit optical elements among the plurality of unit optical elements. An optical system according to embodiment 1 or 2.

[0106] [Aspect 4] The deflection unit includes one or more reflectors that are rotatable around one or more axes of rotation. An optical system of any one of the embodiments 1 to 3.

[0107] [Aspect 5] The deflection unit scans the incident light beam in two dimensions. Optical system of embodiment 1.

[0108] [Aspect 6] The first deflection unit and the second deflection unit scan the incident light beam in directions that intersect each other. Optical system of embodiment 2.

[0109] [Aspect 7] The light beam from the aforementioned optical element is approximately collimated light. An optical system of any one of embodiments 1 to 6.

[0110] [Aspect 8] The light-concentrating position is provided with a light-guiding member that propagates the light beam from the optical element, Optical system of aspect 7.

[0111] [Aspect 9] The two or more reflective surfaces include two mutually orthogonal reflective surfaces. An optical system of any one of embodiments 1 to 8.

[0112] [Aspect 10] The optical element comprises a plate-shaped main body, Each of the plurality of unit optical elements is defined by a protrusion of the light-transmitting material formed on the main body, Both sides of the projection in the longitudinal direction define the inlet portion and the outlet portion, The outer surface of the projection defines the two reflective surfaces. Optical system of aspect 9.

[0113] [Aspect 11] The optical element comprises a main body, Each of the plurality of unit optical elements is defined by a through hole formed in the main body, Both openings of the through hole define the inlet portion and the outlet portion, The inner surface of the through hole defines the two reflective surfaces. Optical system of aspect 9.

[0114] [Aspect 12] In each of the plurality of unit optical elements, the refractive index is n, the size of the incident portion and the output portion is a, the distance between the incident portion and the output portion is t, and the maximum incident angle of the light beam from the deflection portion is θ. max If we use [°], Satisfying TIFF2026144186000010.tif13150, An optical system from any one of embodiments 1 to 11.

[0115] [Aspect 13] In each of the plurality of unit optical elements, the minimum incident angle of the light beam from the deflection portion is set to θ. min If we use [°], Satisfying TIFF2026144186000011.tif13150, Optical system of embodiment 12.

[0116] [Aspect 14] In each of the plurality of unit optical elements, if the refractive index is n, the size of the incident portion and the exit portion is a, and the distance between the incident portion and the exit portion is t, Satisfying TIFF2026144186000012.tif6150, An optical system from any one of embodiments 1 to 11.

[0117] [Aspect 15] In each of the plurality of unit optical elements, if the size of the incident portion and the exit portion is a, and the distance between the incident portion and the exit portion is t, Satisfying TIFF2026144186000013.tif6150, An optical system of any one of embodiments 1 to 10.

[0118] [Aspect 16] If the spacing between the plurality of unit optical elements is c and the beam width of the light beam from the deflection section is d, then d ≥ 2c satisfies, An optical system from any one of the embodiments 1 to 15.

[0119] [Aspect 17] The deflection unit dynamically deflects the incident light beam along a first axis where the deflection unit and the reference position in the optical element for the deflection of the light beam by the deflection unit are aligned when viewed from the normal direction of the virtual plane. The minimum angle of the light beam from the deflection unit with respect to the first axis is θ. ymin [°], The maximum angle of the light beam from the deflection unit with respect to the first axis is θ. ymax [°], If h is the distance between the deflection portion and the optical element in the normal direction of the virtual plane, At least a portion of the plurality of unit optical elements has a distance of h / tanθ from the deflection portion in the direction of the first axis. ymax or more h / tanθ ymin Within the following range: An optical system of any one of embodiments 1 to 16.

[0120] [Aspect 18] The deflection unit dynamically deflects the incident light beam along a second axis perpendicular to the first axis where the deflection unit and the reference position of the deflection of the light beam by the deflection unit in the optical element are aligned, as viewed from the normal direction of the virtual plane. The maximum angle of the light beam with respect to the first axis, from the deflection portion in the first direction along the second axis, is θ. xl [°], The maximum angle of the luminous beam with respect to the first axis is θ, in the second direction opposite to the first direction along the second axis from the deflection portion. xr [°], If L is the distance between the deflection portion and the reference position as viewed from the normal direction of the virtual plane, At least a portion of the plurality of unit optical elements have a distance of Ltanθ from the reference position in the first direction. xl Hereinafter, the distance from the reference position in the second direction is Ltanθ xr Within the following range: An optical system of any one of embodiments 1 to 17.

[0121] Appearances 2-18 are optional elements and not required. [Industrial applicability]

[0122] This disclosure is applicable to optical systems. Specifically, this disclosure is applicable to optical systems for pupil relays. [Explanation of symbols]

[0123] 1. 1A Image Display Device 3, 3A, 3B optical system 4 Deflection section 4a 1st deflection section 4b Second deflection section 41 Reflector 5, 5C optical elements 5a First optical element 5b Second optical related 51, 51C Unit Optical Element 51a First Unit Optical Element 51b Second Unit Optical Element 511 Incidence section 512 Reflector 512a,512b Reflective surface 513 Ejection section 6. Light guide member

Claims

1. A deflection unit that dynamically deflects the incident light beam, An optical element having multiple unit optical elements, Equipped with, Each of the aforementioned plurality of unit optical elements is The incident portion into which the light beam from the deflection portion is incident, A reflecting part that reflects the light beam incident from the aforementioned incident part, A emitting section that emits the light beam reflected by the aforementioned reflective section, Includes, In each of the plurality of unit optical elements, the reflecting portion has two or more reflecting surfaces that reflect the light beam incident from the incident portion an even number of times, such that the light beam from the exit portion is directed toward a focusing position that is plane-symmetric with respect to the deflection portion with respect to a virtual plane between the incident portion of the plurality of unit optical elements and the exit portion of the plurality of unit optical elements. optical system.

2. The deflection unit includes a first deflection unit and a second deflection unit. The optical element includes a first optical element to which a light beam from the first deflection unit is incident, and a second optical element to which a light beam from the second deflection unit is incident. The plurality of unit optical elements include a plurality of first unit optical elements in the first optical element and a plurality of second unit optical elements in the second optical element. In each of the plurality of first unit optical elements, the reflecting portion directs the light beam from the emitting portion toward a first focusing position that is plane-symmetric with respect to the first deflecting portion with respect to a first virtual plane between the incident portion and the emitting portion of the plurality of first unit optical elements. The second deflection unit is located at the first light-gathering position and dynamically deflects the light beam incident from the first optical element. In each of the plurality of second unit optical elements, the reflecting portion directs the light beam from the emitting portion toward a second focusing position that is symmetrical with the second deflecting portion with respect to a second virtual plane between the incident portion and the emitting portion of the plurality of second unit optical elements. The optical system according to claim 1.

3. The plurality of unit optical elements are arranged such that the rays from both outer edges that define the beam width of the light beam from the deflection portion are reflected an even number of times by the reflecting portions of different unit optical elements among the plurality of unit optical elements. The optical system according to claim 1.

4. The deflection unit includes one or more reflectors that are rotatable around one or more rotation axes. The optical system according to claim 1.

5. The deflection unit scans the incident light beam in two dimensions. The optical system according to claim 1.

6. The first deflection unit and the second deflection unit scan the incident light beam in directions that intersect each other. The optical system according to claim 2.

7. The light beam from the aforementioned optical element is approximately collimated light. The optical system according to claim 1.

8. The light-concentrating position is provided with a light-guiding member that propagates the light beam from the optical element, The optical system according to claim 7.

9. The two or more reflective surfaces include two mutually orthogonal reflective surfaces. The optical system according to claim 1.

10. The optical element comprises a plate-shaped main body, Each of the aforementioned plurality of unit optical elements is defined by a protrusion of the light-transmitting material formed on the main body, Both sides of the projection in the longitudinal direction define the inlet portion and the outlet portion, The outer surface of the projection defines the two reflective surfaces. The optical system according to claim 9.

11. The optical element comprises a main body, Each of the plurality of unit optical elements is defined by a through hole formed in the main body, Both openings of the through hole define the inlet portion and the outlet portion, The inner surface of the through hole defines the two reflective surfaces. The optical system according to claim 9.

12. In each of the plurality of unit optical elements, the refractive index is n, the size of the incident portion and the output portion is a, the distance between the incident portion and the output portion is t, and the maximum incident angle of the light beam from the deflection portion is θ. ｍａｘ If we use [°], Satisfying The optical system according to claim 1.

13. In each of the plurality of unit optical elements, the minimum incident angle of the light beam from the deflection portion is set to θ. ｍｉｎ If we use [°], Satisfying The optical system according to claim 12.

14. In each of the plurality of unit optical elements, if the refractive index is n, the size of the incident portion and the exit portion is a, and the distance between the incident portion and the exit portion is t, Satisfying The optical system according to claim 1.

15. In each of the plurality of unit optical elements, if the size of the incident portion and the exit portion is a, and the distance between the incident portion and the exit portion is t, Satisfying The optical system according to claim 1.

16. If the spacing between the plurality of unit optical elements is c and the beam width of the light beam from the deflection section is d, then d ≥ 2c satisfies, The optical system according to claim 1.

17. The deflection unit dynamically deflects the incident light beam along a first axis where the deflection unit and the reference position in the optical element for the deflection of the light beam by the deflection unit are aligned when viewed from the normal direction of the virtual plane. The minimum angle of the light beam from the deflection unit with respect to the first axis is θ. ｙｍｉｎ [°], The maximum angle of the light beam from the deflection unit with respect to the first axis is θ. ｙｍａｘ [°], If h is the distance between the deflection portion and the optical element in the normal direction of the virtual plane, At least a portion of the plurality of unit optical elements has a distance of h / tanθ from the deflection portion in the direction of the first axis. ｙｍａｘ or more h / tanθ ｙｍｉｎ Within the following range: The optical system according to claim 1.

18. The deflection unit dynamically deflects the incident light beam along a second axis perpendicular to the first axis where the deflection unit and the reference position of the deflection of the light beam by the deflection unit in the optical element are aligned, as viewed from the normal direction of the virtual plane. The maximum angle of the light beam with respect to the first axis, from the deflection portion in the first direction along the second axis, is θ. ｘｌ [°], The maximum angle of the luminous beam with respect to the first axis is θ, in the second direction opposite to the first direction along the second axis from the deflection portion. ｘｒ [°], If L is the distance between the deflection portion and the reference position as viewed from the normal direction of the virtual plane, At least a part of the plurality of unit optical elements satisfies, in the optical element, that the distance from the reference position in the first direction is Ltanθ ｘｌ or less, and the distance from the reference position in the second direction is Ltanθ ｘｒ within the following range, The optical system according to claim 1.

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