Display optical system and image display device

Abstract

To provide a simply-configured, compact, and light-weight optical system which offers high optical performance.SOLUTION: A display optical system 10 provided herein comprises a refractive optical system 110 having positive refractive power, a reflective optical system 101 having refractive power and an aperture stop 120, and is configured to allow light emitted from a display surface to pass through the refractive optical system, the reflective optical system and the aperture stop in the described order and enter a light guide 150. The aperture stop is located closer to the light guide than the reflective optical system.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a display optical system that guides image light to a light guide.

Background Art

[0002] An image display device having a display optical system that guides image light generated by a display element such as a DMD (Digital Micromirror Device) to a projection surface such as an observer's pupil or a screen through a light guide is used. Patent Document 1 discloses a display optical system in which a reflection prism is added to a light guide and the image light is guided to the light guide by using total internal reflection in the reflection prism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the display optical system of Patent Document 1, the image light that has passed through the lens unit is made to enter the light guide at once, and the image light that has passed through the light guide is totally internally reflected by the reflection prism and guided to the light guide. In this configuration, since the light guide is arranged so as to be sandwiched between the lens unit and the reflection prism, the size of the light guide becomes large, and as a result, the entire image display device becomes large. In addition, by adding the reflection prism to the light guide, the weight of the display optical system increases. Furthermore, Patent Document 1 does not disclose the numerical data of the display optical system, and it is unclear whether the display optical system has high imaging performance (optical performance).

[0005] The present invention provides a display optical system that can obtain a simple configuration, is small and lightweight, and has high optical performance, and an image display device using the same.

Means for Solving the Problems

[0006] A display optical system having a refractive optical system with a positive refractive power, a reflective optical system with a refractive power, and an aperture stop, and guiding light emitted from a display surface to a light guide through the refractive optical system, the reflective optical system, and the aperture stop in this order, wherein the aperture stop is disposed at a position closer to the light guide than the reflective optical system. Note that an image display device having the above display optical system and the light guide also constitutes another aspect of the present invention.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a display optical system with a simple configuration, small size, light weight, and high optical performance, and an image display device using the same.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

[0009] Hereinafter, examples of the present invention will be described with reference to the drawings.

[0010] FIG. 1, FIG. 4, FIG. 6, FIG. 8, FIG. 10, FIG. 12, and FIG. 14 respectively show cross-sections of the display optical systems 10 to 70 of Examples 1 to 7.

Example

[0011] Here, the display optical system 10 of Example 1 will be described, and matters common to the display optical systems 10 to 70 of Examples 1 to 7 will also be described.

[0012] The display optical system 10 is an optical system that guides the image light emitted from the display surface 130 of the display element to the light guide 150. By the image light passing through the light guide 150 and entering the observer's eye (pupil), the observer can observe the image.

[0013] The display optical system 10 includes a refractive optical system 110 having a positive refractive power, a reflective optical system 101 having a positive or negative refractive power, and an aperture stop 120. The image light that has passed through the aperture stop 120 via the refractive optical system 110 and the reflective optical system 101 in this order is made to enter the light guide 150. The aperture stop 120 is disposed at a position closer to the light guide 150 than the reflective optical system 101. Further, the display optical system 10 is an optical system in which, on the optical axis of the display optical system 10, the position of the aperture stop 120 coincides with the position of the exit pupil of the light emitted from the display surface 130. That is, the aperture stop 120 functions as the exit pupil of the display optical system 10.

[0014] In each embodiment, although a display optical system suitable for image observation is described, the display optical system may be used as an optical system that causes light from a light source to enter an image display device via a light guide.

[0015] The optical member 140 disposed between the display surface 130 and the refractive optical system 110 is an optical member that is not an essential component of the display optical system 10. For example, it is a total reflection prism (TIR) in a DMD element, a light guide prism such as a color separation and synthesis system in a three-panel liquid crystal display optical system, a cover glass for protecting the display element, or the like. The thickness, material, and even the use or non-use of the optical member 140 are appropriately selected according to its configuration and application.

[0016] The refractive optical system 110 having a positive refractive power has a role of refracting the diffused light beam emitted from the display surface 130 and bringing the peripheral light beams of each picture angle closer to parallel light. The refractive optical system 110 is composed of two lenses, a positive lens 111 and a negative lens 112, which are arranged in order from the reflection optical system side to the display surface side. The reflection optical system 101 not only simply reflects the light beam that has passed through it, but also has a role of condensing the principal rays of all picture angles with respect to the aperture stop 120 while bringing the peripheral light beams of each picture angle closer to parallel light.

[0017] According to such a configuration, the refractive power is shared between the refractive optical system 110 and the reflection optical system 101, contributing to miniaturization as a whole. Also, since aberration correction is shared between the refractive optical system 110 and the reflection optical system 101, the display optical system 10 has high optical performance as a whole. The refractive optical system 110 mainly corrects field curvature and astigmatism, and the reflection optical system 101 mainly corrects coma aberration and spherical aberration. Furthermore, if the reflection optical system 101 has refractive power, the refractive power of the refractive optical system 110 can be reduced, so that chromatic aberration can be reduced well as a whole. As a result, it is possible to configure the refractive optical system 110 with a small number of lenses, and it is possible to realize a display optical system that is small and lightweight as a whole.

[0018] The light guide 150 receives the light beam (image light) guided by the display optical system 10. The light guide 150 is composed of a light-transmissive member such as glass or resin, and is configured to propagate the light beam in the light guide 150 by using an internal reflection prism, total internal reflection, etc. Such a light guide 150 is suitable for an image display device as an application example, in which the light guide 150 appears as a transparent member from the outside while propagating the image light inside. The method of guiding the light to the observer's eyes by the light guide 150 can be appropriately selected according to the specifications and design conditions of the image display device.

[0019] Also, the aperture stop 120 is disposed on the light guide side with respect to the reflection optical system 101. That is, the image light emitted from the display surface 130 is reflected by the reflection optical system 101 and then enters the aperture stop 120. The aperture stop 120 is preferably disposed at a position close to the incident surface of the light guide 150. Thereby, the aperture stop 120 and the light guide 150 can be held by the same holding member. However, the aperture stop 120 may be held by a member different from the member holding the light guide 150 and disposed with air separated at a position away from the light guide 150, or the aperture stop 120 may be embedded inside the light guide 150.

[0020] The display optical system 10 is mainly configured as an oblique display optical system in which the light beam is incident obliquely on the light guide 150. The incident angle of the principal ray of each angular field of view on the light guide 150 is about 20° to 50°. The incident angle of the principal ray may be larger or smaller than this. For example, in the first embodiment, the total angular field (total field of view: FOV) in the angular field distribution direction Y shown in FIG. 1 is 30°. Such a configuration is preferable because the display surface 130 and the light guide 150 are closer to being parallel, contributing to the overall thinning.

[0021] In addition, in the display optical system 10, the reflection optical system 101 mainly plays the role of obliquely incidenting a light beam on the light guide 150. Therefore, with respect to the light guide 150, the reflection optical system 101 is more eccentric in the inclination direction than the refractive optical system 110. In each embodiment, the inclination eccentricity amount of the refractive optical system with respect to the light guide is 0° in all cases. However, if necessary, an inclination eccentricity amount with respect to the light guide may be given to the refractive optical system. In this case, it is preferable that the absolute value of the inclination eccentricity amount is smaller than the absolute value of the inclination eccentricity amount of the reflection optical system with respect to the light guide. According to this configuration, the three components of the refractive optical system 110, the reflection optical system 101, and the light guide 150 can be arranged closer to each other, and a smaller display optical system can be obtained.

[0022] The reflection optical system 101 is composed of a concave reflecting surface having a positive refractive power. According to this configuration, the refractive power of the refractive optical system 110 can be reduced, the aberration generated in the refractive optical system 110 can be reduced, and it contributes to the miniaturization and high performance of the display optical system 10. Note that the reflection optical system only needs to have a refractive power and may have a negative refractive power.

[0023] FIG. 2 schematically shows the distance and axis in the display optical system 10. Since the display optical system 10 is an eccentric optical system and a strict optical axis cannot be defined, the axis defined as follows is used for convenience.

[0024] The vertex of the surface of the refractive optical system 110 closest to the reflection optical system side is defined as the first refraction point Prf, and a straight line perpendicular to the display surface 130 and passing through the first refraction point Prf is defined as the Z-axis as the first axis. The intersection point of the Z-axis and the surface of the refractive optical system 110 closest to the display surface side is defined as the second refraction point Prr. Further, the intersection point of the Z-axis and the reflection optical system 101 is defined as the reflection point Pm. Specifically, the vertex of the surface of the refractive optical system 110 closest to the reflection optical system side corresponds to the vertex of the surface of the lens 111 on the reflection optical system side. The vertex of the surface corresponds to the center of curvature of the surface of the lens 111 on the reflection optical system side. Also, the first refraction point Prf is the point that protrudes most toward the reflection optical system side on the surface of the lens 111 on the reflection optical system side.

[0025] In the above definition, let the distance on the Z-axis between the first refraction point Prf and the reflection point Pm be Lm. Lm represents the distance between the refractive optical system 110 and the reflective optical system 101 on the Z-axis. Also, let the distance on the Z-axis between the first refraction point Prf and the second refraction point Prr be Lr. In other words, Lr represents the total length of the refractive optical system 110 on the Z-axis.

[0026] Furthermore, let the distance on the Z-axis between the display surface 130 and the second refraction point Prr be Lb. Lb represents the distance between the refractive optical system 110 and the display surface 130 on the Z-axis, and substantially corresponds to the back focus of the display optical system 10. In addition, let the minimum distance between the aperture stop 120 and the plane passing through the reflection point Pm and parallel to the display surface 130 be Lst. Lst serves as an index indicating the distance between the reflective optical system 101 and the aperture stop 120. Also, let the distance between the incident surface 151 of the light guide 150 and the aperture stop 120 be L0.

[0027] Under the above definitions, it is preferable that the display optical system 10 satisfies at least one of the conditions of the following formulas (1) to (4).

[0028] First, when the focal length of the refractive optical system 110 is fr, it is preferable that the display optical system 10 satisfies the condition of the following formula (1).

[0029] |L0 / fr|≦0.3 (1) The condition of Equation (1) indicates that it is preferable that the aperture stop 120 is disposed at a position close to the incident surface 151 of the light guide 150. By satisfying the condition of Equation (1), it becomes possible to reduce the diameter of the passing light beam at the incident surface 151 of the light guide, and it becomes possible to miniaturize the light guide 150. When the aperture stop 120 is disposed away from the incident surface 151 of the light guide 150 toward the reflection optical system side (the right side in the figure) such that |L0 / fr| exceeds the upper limit of Equation (1), it is necessary to increase the distance between the aperture stop 120 and the reflection optical system 101, and the display optical system 10 becomes larger as a whole. Further, since it is necessary to increase the diameter of the incident surface 151 of the light guide 150, this is not preferable. Also, when the aperture stop 120 is disposed inside the light guide 150 (the left side in the figure) rather than the incident surface 151 of the light guide 150 such that |L0 / fr| exceeds the upper limit of Equation (1), the light guide 150 becomes thicker, leading to an increase in the size and weight of the display optical system 10 as a whole, which is not preferable.

[0030] In each embodiment, the distance L0 between the incident surface of the light guide 150 and the aperture stop 120 is 0, and thus |L0 / fr| is 0. However, the position of the aperture stop 120 may be changed within a range that satisfies the condition of Equation (1) from the viewpoint of heat dissipation and the like.

[0031] Note that it is more preferable if the numerical range of Equation (1) is as follows.

[0032] |L0 / fr| ≦ 0.1 (1a) Also, it is even more preferable if the numerical range of Equation (1) is as follows.

[0033] |L0 / fr| ≦ 0.01 (1b) Also, the display optical system 10 preferably satisfies the condition of the following Equation (2).

[0034] 1.0 ≦ Lst / Lm ≦ 2.2 (2) The condition of formula (2) indicates the appropriate positional relationship among the refractive optical system 110, the reflective optical system 101, and the aperture stop 120. By satisfying the condition of formula (2), it becomes possible to make the light beam with a wide angle of view incident on the aperture stop 120 without interference. If Lst / Lm exceeds the upper limit of formula (2), the light beam on the high angle-of-view side interferes with the refractive optical system 110 and the angle of view cannot be widened, which is not preferable. If Lst / Lm is below the lower limit of formula (2), the reflective optical system 101 is too far from the refractive optical system 110 (Lm becomes too large), which leads to an increase in the size of the display optical system 10 and deterioration of optical performance, so it is not preferable.

[0035] In addition, it is more preferable if the numerical range of formula (2) is as follows.

[0036] 1.2 ≦ Lst / Lm ≦ 1.9 (2a) Also, it is even more preferable if the numerical range of formula (2) is as follows.

[0037] 1.40 ≦ Lst / Lm ≦ 1.65 (2b) In addition, it is preferable that the display optical system 10 satisfies the condition of the following formula (3).

[0038] 0.2 ≦ Lr / Lm ≦ 1.4 (3) The condition of formula (3) indicates the appropriate relationship between the overall length of the refractive optical system 110 and the distance between the refractive optical system 110 and the reflective optical system 101. By satisfying the condition of formula (3), miniaturization of the display optical system 10 is possible. If Lr / Lm exceeds the upper limit of formula (3), the overall length of the refractive optical system 110 becomes too large, the display optical system 10 becomes large, and the possibility of the light beam on the high angle-of-view side interfering with the refractive optical system 110 increases, inhibiting widening of the angle of view, so it is not preferable. If Lr / Lm is below the lower limit of formula (3), the overall length of the refractive optical system 110 becomes too short, making it difficult to ensure the flange portion provided around each lens and the edge interval between the lenses, so it is not preferable.

[0039] In addition, it is more preferable if the numerical range of formula (3) is as follows.

[0040] 0.3 ≤ Lr / Lm ≤ 0.9 (3a) Also, it is more preferable if the numerical range of formula (3) is as follows.

[0041] 0.40 ≤ Lr / Lm ≤ 0.75 (3b) Furthermore, it is preferable that the display optical system 10 satisfies the condition of the following formula (4).

[0042] 0.005 ≤ |Lb / fr| ≤ 0.700 (4) The condition of formula (4) indicates an appropriate relationship between the focal length of the refractive optical system 110 and the distance between the refractive optical system 110 and the display surface 130. By satisfying the condition of formula (4), good optical performance can be obtained while appropriately maintaining the optical distance between the refractive optical system 110 and the aperture stop 130. If |Lb / fr| exceeds the upper limit of formula (4), the refractive power of the refractive optical system 110 becomes too large, resulting in a decrease in optical performance, and the aperture stop 130 approaches the reflective optical system 101 too closely, causing light interference, which is not preferable. Moreover, since a re-imaging point occurs before the light beam reaches the light guide 150 and the optical system no longer holds, it is not preferable. If |Lb / fr| is below the lower limit of formula (4), the back focus of the display optical system 10 becomes too short, making it impossible to arrange optical members such as prisms and cover glasses, which is not preferable.

[0043] In addition, it is more preferable if the numerical range of formula (4) is as follows.

[0044] 0.01 ≤ |Lb / fr| ≤ 0.50 (4a) Also, it is more preferable if the numerical range of formula (4) is as follows.

[0045] 0.015 ≤ |Lb / fr| ≤ 0.300 (4b) The display optical system 10 preferably satisfies at least one of the following configurations.

[0046] First, it is preferable that the space between the refractive optical system 110 and the reflective optical system 101 is filled with air, at least on the Z-axis. The light beam passing between the refractive optical system 110 and the reflective optical system 101 has a complex optical path because both the incident light beam and the reflected light beam pass through the reflective optical system 101, and the angle is relatively steep on the reflection side. Therefore, it is advisable to use air from the perspective of preventing ghosts caused by stray light.

[0047] Also, the refractive optical system 110 preferably includes at least one positive lens and at least one negative lens. With this configuration, it becomes possible to share aberration correction within the refractive optical system 110, and it becomes possible to correct field curvature and chromatic aberration well. Note that it is more preferable for the refractive optical system 110 to have at least three lenses including a positive lens and a negative lens. With this configuration, aberration correction can be performed more finely, and the optical performance can be improved.

[0048] Also, the lens on the reflective optical system side that is closest to the refractive optical system 110 is preferably a positive lens. With this configuration, the light beam emitted from the refractive optical system 110 can be made closer to a parallel light beam and incident on the reflective optical system 101 as an appropriate light beam.

[0049] Furthermore, the surface on the reflective optical system side of the lens on the reflective optical system side that is closest to the refractive optical system 110 is preferably a convex surface. With this configuration, not only can appropriate spherical aberration correction be performed on the light beam emitted from the refractive optical system 110, but also interference with the light beam on the high image angle side among the light beams reflected by the reflective optical system 101 can be avoided, and the image angle can be widened.

[0050] After Example 7 described later, Numerical Examples 1 to 7 corresponding to each of Examples 1 to 7 are shown. FIG. 3 shows the lateral aberration of the display optical system 10 of Numerical Example 1. The display optical system 10 of Example 1 (Numerical Example 1) has a simple configuration, is small and lightweight, and has high optical performance capable of correcting aberrations well.

Example

[0051] The display optical system 20 of Example 2 shown in FIG. 4 is an optical system that makes the image on the display surface 230 incident on the aperture stop 420 as a pupil. The display optical system 20 includes a refractive optical system 210 having a positive refractive power, a reflective optical system 201 having a positive refractive power, and an aperture stop 220, and guides the image light that has passed through the aperture stop 220 through the refractive optical system 210 and the reflective optical system 201 in this order to the light guide 250. An optical member 240 similar to the optical member 140 in Example 1 is disposed between the display surface 230 and the refractive optical system 210.

[0052] The refractive optical system 210 is composed of three lenses, namely, a positive lens 211, a positive lens 212, and a negative lens 213, which are arranged in order from the reflective optical system side to the display surface side. With this configuration, the space between the positive lens 211 and the positive lens 212 can be used as an air lens for aberration correction, and particularly, spherical aberration can be corrected well.

[0053] FIG. 5 shows the lateral aberration of the display optical system 20 of Numerical Example 2. The display optical system 20 of Example 2 (Numerical Example 2) has a simple configuration, is small in size, and has high optical performance with well-corrected aberrations. In particular, the spherical aberration on the low angle side in the Y field angle (tangential) and the aberration in the middle field angle in the X field angle (sagittal) are well suppressed.

Example

[0054] The display optical system 30 of Example 3 shown in FIG. 6 is an optical system that makes the image on the display surface 330 incident on the aperture stop 320 as a pupil. The display optical system 30 includes a refractive optical system 310 having a positive refractive power, a reflective optical system 301 having a positive refractive power, and an aperture stop 320, and guides the image light that has passed through the aperture stop 320 through the refractive optical system 310 and the reflective optical system 301 in this order to the light guide 350. An optical member 340 similar to the optical member 140 in Example 1 is disposed between the display surface 330 and the refractive optical system 310.

[0055] The refractive optical system 310 is composed of three lenses, namely, a positive lens 311, a negative lens 312, and a negative lens 313, which are arranged in order from the reflection optical system side to the display surface side. With this configuration, the ratio of the hollow region within the refractive optical system 110 can be increased, and the entire display optical system 20 can be lightened.

[0056] FIG. 7 shows the lateral aberration of the display optical system 30 of Numerical Example 3. The display optical system 30 of Example 3 (Numerical Example 3) has a simple configuration, is small and lightweight, and has high optical performance capable of well correcting aberrations. In particular, the display optical system 30 is smaller than those of Examples 1 and 2.

Example

[0057] The display optical system 40 of Example 4 shown in FIG. 8 is an optical system that makes the image on the display surface 430 incident as a pupil with respect to the aperture stop 420. The display optical system 40 includes a refractive optical system 410 having a positive refractive power, a reflective optical system 401 having a positive refractive power, and an aperture stop 420, and guides the image light that has passed through the aperture stop 420 to the light guide 450 through the refractive optical system 410 and the reflective optical system 401 in this order. An optical member 440 similar to the optical member 140 in Example 1 is disposed between the display surface 430 and the refractive optical system 410.

[0058] The refractive optical system 410 is composed of two lenses, namely, a positive lens 411 and a negative lens 412, which are arranged in order from the reflection optical system side to the display surface side.

[0059] The display optical system 40 of Example 4 has a configuration with a shorter back focus than other examples. This configuration is suitable, for example, when a self-luminous color panel is used as a display element.

[0060] FIG. 9 shows the lateral aberration of the display optical system 40 of Numerical Example 4. The display optical system 40 of Example 4 (Numerical Example 4) has a simple configuration, is small and lightweight, and has high optical performance capable of well correcting aberrations. In particular, it can correct each aberration extremely well while being small.

Example

[0061] The display optical system 50 of Example 5 shown in FIG. 10 is an optical system that makes the image on the display surface 530 enter the aperture stop 520 as a pupil. The display optical system 50 includes a refractive optical system 510 having a positive refractive power, a reflective optical system 501 having a positive refractive power, and an aperture stop 520, and guides the image light that has passed through the aperture stop 520 to the light guide 550 through the refractive optical system 510 and the reflective optical system 501 in this order. An optical member 540 similar to the optical member 140 in Example 1 is disposed between the display surface 530 and the refractive optical system 510.

[0062] The refractive optical system 510 is composed of two lenses, a positive lens 511 and a negative lens 512, which are arranged in order from the reflective optical system side to the display surface side.

[0063] The display optical system 50 of Example 5 has a configuration with a longer back focus than other examples. This configuration is used, for example, when synthesizing three-color image light emitted from three-color display elements using a prism.

[0064] FIG. 11 shows the lateral aberration of the display optical system 50 of Numerical Example 5. The display optical system 50 of Example 5 (Numerical Example 5) has a simple configuration, is small and lightweight, and has high optical performance capable of well correcting aberrations. In particular, it can well correct aberrations while having a particularly long back focus.

Example

[0065] The display optical system 60 of Example 6 shown in FIG. 12 is an optical system that makes the image on the display surface 630 enter the aperture stop 620 as a pupil. The display optical system 60 includes a refractive optical system 610 having a positive refractive power, a reflective optical system 601 having a positive refractive power, and an aperture stop 620, and guides the image light that has passed through the aperture stop 620 to the light guide 650 through the refractive optical system 610 and the reflective optical system 601 in this order. An optical member 640 similar to the optical member 140 in Example 1 is disposed between the display surface 630 and the refractive optical system 610.

[0066] The refractive optical system 610 is composed of two lenses, a positive lens 611 and a negative lens 612, arranged in order from the reflection optical system side to the display surface side.

[0067] The display optical system 60 of Example 6 has a configuration in which the distance between the light guide 650 and the aperture stop 620 is wider than that of other examples. With this configuration, the space between the light guide 650 and the reflection optical system 601 can be widened, and a plurality of mechanical members such as a holding member for holding the refractive optical system 610 and the aperture stop 620 can be packed and arranged in the above space without interfering the light beam traveling from the reflection optical system 601 toward the aperture stop 620 with the refractive optical system 610.

[0068] FIG. 13 shows the lateral aberration of the display optical system 60 of Numerical Example 6. The display optical system 60 of Example 6 (Numerical Example 6) has a simple configuration, is small and lightweight, and has high optical performance capable of correcting aberrations well.

Example

[0069] The display optical system 70 of Example 7 shown in FIG. 14 is an optical system that makes the image on the display surface 730 enter the aperture stop 720 as a pupil. The display optical system 70 includes a refractive optical system 710 having a positive refractive power, a reflection optical system 701 having a positive refractive power, and an aperture stop 720, and makes the image light that has passed through the aperture stop 720 enter the light guide 750 through the refractive optical system 710 and the reflection optical system 701 in this order. An optical member 740 similar to the optical member 140 in Example 1 is arranged between the display surface 730 and the refractive optical system 710.

[0070] The refractive optical system 710 is composed of two lenses, a positive lens 711 and a negative lens 712, arranged in order from the reflection optical system side to the display surface side.

[0071] The display optical system 70 of Example 7 has a configuration in which the distance between the light guide 750 and the aperture stop 720 and the reflective optical system 701 is made larger than that of other examples. In this configuration, the light guide 750 is arranged farther from the refractive optical system 710 and the display surface 730. Therefore, this configuration is effective when it is desired to separate the light guide 750 from a light source system (not shown) associated with the display surface 730, etc.

[0072] FIG. 15 shows the lateral aberration of the display optical system 70 of Numerical Example 7. The display optical system 70 of Example 7 (Numerical Example 7) has a simple configuration, is small and lightweight, and has high optical performance capable of well correcting aberrations.

[0073] Hereinafter, Numerical Examples 1 to 7 are shown. For various data, the Y focal length (mm), which is the focal length in the angular distribution direction of the picture angle, the aperture stop diameter (mm), and the Y full field of view (FOV) (°) are shown. The Y focal length (mm) and the FOV (°) are values calculated for the wavelength λ = 550 nm with the object distance as the reference distance. Also, in each numerical example, the display side is set as the image, and the emission side leading to the observer's pupil is set as the object.

[0074] In the surface data, the surface number i indicates the order of the surfaces counted from the light guide plate (object) side. Note that "object" and "image" in the surface numbers are virtual in the optical design. (Aperture stop) attached to the surface number indicates that the surface is the aperture stop. "Radius of curvature" indicates the radius of curvature (mm) of the i-th surface, and "axial distance" indicates the on-axis distance (distance on the optical axis) between the i-th surface and the (i + 1)-th surface (mm). A minus sign attached to the axial distance indicates that coordinate conversion has been performed by reflection. nd indicates the refractive index of the optical material between the i-th surface and the (i + 1)-th surface at the d-line, and νd indicates the Abbe number of the optical material based on the d-line. The Abbe number νd based on the d-line is when the refractive indices at the d-line (587.6 nm), F-line (486.1 nm), and C-line (656.3 nm) of the Fraunhofer lines are Nd, NF, and NC, respectively, νd=(Nd - 1) / (NF - NC) is represented by.

[0075] Regarding the coordinate transformation due to eccentricity, the vertical parallel eccentricity within the cross-sectional view is shown as the Y eccentricity, and the clockwise and counterclockwise tilt eccentricities within the cross-sectional view are shown as the α eccentricity. The unit of the parallel eccentricity is mm, and the unit of the tilt eccentricity is °.

[0076] When the surface is an XY polynomial surface, (polynomial) is appended to the surface number of that surface. The surface shape of the XY polynomial surface is expressed by the following formula when x and y are the displacement amounts on the x-axis and y-axis respectively from the surface vertex in the optical axis direction, r is the paraxial curvature radius, c is the y vertex curvature, k is the conic constant, and C is the aspherical coefficient. "E±M" of the aspherical coefficient means ×10 ±M is meant.

[0077]

Number

[0078] Below the surface data, the values corresponding to each degree of x and y of the aspherical coefficient C are shown. For example, X**2 and Y**4 are the aspherical coefficients corresponding to x 2 and y 4 respectively. The aspherical coefficients of the degrees without notation are all 0.

[0079] Table 1 summarizes the values related to the conditions of the above-mentioned formulas (1) to (4). The display optical system of each numerical example satisfies all the conditions of formulas (1) to (4). [Numerical Example 1] (mm) Various data Y focal length 13.50 Aperture stop diameter 2 Y full field of view (FOV) 30° Surface data Surface number Curvature radius Surface interval nd νd Reflective surface Y eccentricity α eccentricity Object Infinity Infinity 1 Infinity 2.000 1.51633 64.14 2 (stop) Infinity 10.769 3 (polynomial) -37.342 -7.476 Reflective -3.10 -10.23 4 -5.691 -3.190 1.51633 64.14 -7.33 5 66.040 -1.044 6 37.185 -0.600 1.80810 22.76 7 -11.976 -0.617 8 Infinite -3.000 1.51633 64.14 Image Infinite 0.000 Configuration of Polynomial Surface Radius of Curvature and Conic Coefficient Radius of Y Curvature (r) -37.342 Vertex Curvature (c) -0.0268 Normalized Radius 0.000 Conic Coefficient (k) -4.758 Polynomial Coefficient X**0 X**2 X**4 X**6 X**8 X**10 Y**0 0.000E+00 0.000E+00 -4.687E-05 5.104E-04 -7.413E-04 3.163E-04 Y**2 0.000E+00 -1.218E-04 -1.124E-05 3.062E-06 8.674E-07 0.000E+00 Y**4 -1.544E-06 2.578E-06 2.436E-07 -7.919E-08 0.000E+00 0.000E+00 Y**6 -1.918E-07 -5.696E-08 -7.561E-10 0.000E+00 0.000E+00 0.000E+00 Y**8 2.451E-09 4.427E-10 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Y**10 -1.246E-11 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 [Numerical Example 2] (mm) Various Data Y focal length 13.56 Aperture diameter 2 Y full field of view (FOV) 30° Surface data Surface number, radius of curvature, surface interval, nd, νd, reflecting surface, Y eccentricity, α eccentricity Object: infinity, infinity 1: infinity, 2.000, 1.51633, 64.14 2 (diaphragm): infinity, 10.664 3 (polynomial): -35.534, -7.364, reflecting, -3.86, -11.42 4: -6.167, -1.656, 1.88300, 40.77, -7.23 5: -15.151, -0.091 6: -17.933, -1.116, 1.77250, 49.60 7: 49.177, -0.203 8: 42.871, -0.600, 1.7783, 23.91 9: -5.900, -1.360 10: infinity, -3.000, 1.51633, 64.14 11: infinity, 0.000 Configuration of polynomial surface Radius of curvature and conic coefficient Y radius of curvature -35.534 Vertex curvature (c) -0.0281 Normalized radius 0.000 Conic coefficient (k) -11.583 Polynomial coefficients X**0, X**2, X**4, X**6, X**8, X**10 Y**0: 0.000E+00, 0.000E+00, -1.978E-04, 5.688E-04, -7.413E-04, 3.163E-04 Y**2: 0.000E+00, -2.117E-04, 7.090E-06, -3.442E-06, 8.674E-07, 0.000E+00 Y**4 -9.483E-06 6.339E-06 -3.455E-07 3.543E-08 0.000E+00 0.000E+00 Y**6 -6.117E-07 -1.749E-07 4.979E-09 0.000E+00 0.000E+00 0.000E+00 Y**8 1.150E-08 1.656E-09 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Y**10 -7.653E-11 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 [Numerical Example 3] (mm) Various data Y Focal length 13.69 Aperture diameter 2 Y Full field of view (FOV) 30° Surface data Surface number Radius of curvature Surface interval nd νd Reflective surface Y eccentricity α eccentricity Object Infinity Infinity 1 Infinity 2.000 1.51633 64.14 2 (Diaphragm) Infinity 4.760 3 (Polynomial) -195.216 -1.688 Reflective 15.84 32.90 4 -6.252 -2.364 1.804 46.53 -7.02 5 -17.819 -0.501 6 -17.770 -0.442 1.94595 17.98 7 -7.694 -1.132 8 48.266 -0.500 1.48749 70.24 9 208.486 -0.174 10 Infinity -3.000 1.51633 64.14 11 Infinity 0.000 Composition of polynomial surface Radius of curvature and conic coefficient Y Curvature Radius -195.216 Vertex Curvature (c) -0.0051 Normalized Radius 0.000 Conic Coefficient (k) 25.360 Polynomial Coefficient X**0 X**2 X**4 X**6 X**8 X**10 Y**0 0.000E+00 0.000E+00 -1.570E-02 2.011E-02 -4.409E-03 1.014E-03 Y**2 0.000E+00 -9.351E-05 4.381E-05 -7.441E-05 4.829E-06 0.000E+00 Y**4 -5.608E-05 1.268E-07 2.787E-08 7.226E-08 0.000E+00 0.000E+00 Y**6 4.104E-08 1.555E-10 -1.057E-10 0.000E+00 0.000E+00 0.000E+00 Y**8 3.516E-11 -4.838E-13 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Y**10 -6.154E-14 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 [Numerical Example 4] (mm) Various Data Y Focal Length 14.59 Aperture Stop Diameter 2 Y Full Field of View (FOV) 30° Surface Data Surface Number Curvature Radius Surface Interval nd νd Reflective Surface Y Eccentricity α Eccentricity Object Infinity Infinity 1 Infinity 2.000 1.51633 64.14 2 (Stop) Infinity 12.398 3 (Polynomial) -32.6090 -8.635 Reflective -6.39 -2.27 4 -6.0000 -3.738 1.51633 64.14 -7.83 5 38.3919 -0.465 6 -84.3201 -0.600 1.80810 22.76 7 -6.0118 -1.105 8 Infinite -0.800 1.51633 64.14 Image Infinite 0.000 Configuration of polynomial surface Radius of curvature and conic coefficient Radius of curvature in Y -32.609 Vertex curvature (c) -0.0307 Normalized radius 0.000 Conic coefficient (k) -2.034 Polynomial coefficients X**0 X**2 X**4 X**6 X**8 X**10 Y**0 0.000E+00 0.000E+00 -2.519E-04 6.188E-04 -7.413E-04 3.163E-04 Y**2 0.000E+00 -9.542E-05 5.942E-06 -4.318E-06 8.674E-07 0.000E+00 Y**4 -6.620E-06 1.379E-06 -5.650E-08 2.065E-08 0.000E+00 0.000E+00 Y**6 -8.407E-09 -2.230E-08 1.611E-10 0.000E+00 0.000E+00 0.000E+00 Y**8 -1.152E-10 1.162E-10 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Y**10 6.636E-13 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 [Numerical Example 5] (mm) Various data Y focal length 13.12 Aperture diameter 2 Y full field of view (FOV) 30° Surface data Surface number, radius of curvature, surface interval, nd, νd, reflecting surface, Y eccentricity, α eccentricity Object: Infinity, Infinity 1: Infinity, 2.000, 1.51633, 64.14 2 (diaphragm): Infinity, 10.139 3 (polynomial): -43.282, -7.064, reflecting, -2.43, -10.77 4: -6.188, -2.816, 1.51633, 64.14, -7.00 5: -47.713, -0.735 6: -34.631, -0.500, 1.80810, 22.76 7: -13.518, -0.693 8: Infinity, -6.000, 1.51633, 64.14 Image: Infinity, 0.000 Composition of polynomial surface Radius of curvature and conic coefficient Y radius of curvature -43.282 Vertex curvature (c) -0.0231 Normalized radius 0.000 Conic coefficient (k) 5.564 Polynomial coefficients X**0, X**2, X**4, X**6, X**8, X**10 Y**0: 0.000E+00, 0.000E+00, 4.102E-05, 5.039E-04, -7.413E-04, 3.163E-04 Y**2: 0.000E+00, -1.193E-04, 1.960E-05, -1.129E-05, 8.674E-07, 0.000E+00 Y**4: 8.295E-06, 5.276E-06, -6.419E-07, 1.777E-07, 0.000E+00, 0.000E+00 Y**6 -1.085E-07 -1.028E-07 4.590E-09 0.000E+00 0.000E+00 0.000E+00 Y**8 3.525E-09 7.127E-10 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Y**10 -2.111E-11 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 [Numerical Example 6] (mm) Various data Y focal length 12.31 Aperture diameter 2 Y full field of view (FOV) 30° Surface data Surface number Radius of curvature Surface interval nd νd Reflective surface Y eccentricity α eccentricity Object Infinity Infinity 1 Infinity 5.000 1.51633 64.14 2 Infinity 5.000 3 (Diaphragm) Infinity 9.272 -2.85 -10.45 4 (Polynomial) -37.926 -9.262 Reflective -7.00 5 -5.298 -3.640 1.51633 64.14 6 59.251 -0.100 7 -260.625 -0.500 1.80810 22.76 8 -10.875 -0.744 9 Infinity -3.000 1.51633 64.14 Image Infinity 0.000 Composition of polynomial surface Radius of curvature and conic coefficient Y radius of curvature -37.926 Vertex curvature (c) -0.0264 Normalized radius 0.000 Conic coefficient (k) -5.724 Polynomial coefficient X**0 X**2 X**4 X**6 X**8 X**10 Y**0 0.000E+00 0.000E+00 1.448E-04 4.144E-04 -7.413E-04 3.163E-04 Y**2 0.000E+00 -1.501E-04 -4.229E-05 1.485E-05 8.674E-07 0.000E+00 Y**4 7.658E-06 5.031E-06 1.296E-06 -3.465E-07 0.000E+00 0.000E+00 Y**6 -5.495E-07 -1.447E-07 -8.977E-09 0.000E+00 0.000E+00 0.000E+00 Y**8 1.018E-08 1.475E-09 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Y**10 -6.840E-11 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 [Numerical Example 7] (mm) Various data Y focal length 21.92 Aperture diameter 2.00 Y full field of view (FOV) 20.00° Surface data Surface number Radius of curvature Surface interval nd νd Reflective surface Y eccentricity α eccentricity Object Infinity Infinity 1 Infinity 2.000 1.51633 64.14 2 (Diaphragm) Infinity 23.655 3 (Polynomial) -43.816 -13.160 Reflective -8.67 -8.10 4 -6.008 -2.981 1.51633 64.14 -13.89 5 -18.406 -0.626 6 -12.851 -0.500 1.80810 22.76 7 - 6.501 - 1.052 8 Infinite - 3.000 1.51633 64.14 Image Infinite 0.000 Configuration of Polynomial Surface Radius of Curvature and Conic Coefficient Radius of Y - curvature - 43.816 Vertex Curvature (c) - 0.0228 Normalized Radius 0.000 Conic Coefficient (k) - 4.496 Polynomial Coefficient X**0 X**2 X**4 X**6 X**8 X**10 Y**0 0.000E+00 0.000E+00 - 1.866E - 04 5.757E - 04 - 7.413E - 04 3.163E - 04 Y**2 0.000E+00 - 5.320E - 05 2.602E - 06 - 4.806E - 07 - 4.664E - 08 0.000E+00 Y**4 1.879E - 07 8.025E - 07 - 6.788E - 08 6.266E - 09 0.000E+00 0.000E+00 Y**6 - 9.375E - 08 - 1.137E - 08 4.446E - 10 0.000E+00 0.000E+00 0.000E+00 Y**8 6.139E - 10 5.490E - 11 0.000E+00 0.000E+00 0.000E+00 0.000E+00 Y**10 - 1.751E - 12 0.000E+00 0.000E+00 0.000E+00 0.000E+00 0.000E+00 [Table 1] Numerical Examples 1 2 3 4 5 6 7 Lb 3.617 4.360 3.174 1.905 6.693 3.744 4.052 Lr 4.834 3.666 4.938 4.803 4.051 4.240 4.107 Lm 6.458 6.512 5.889 7.517 5.934 8.257 12.092 Lst 9.750 9.812 8.961 11.280 9.008 8.267 22.587 L0 0.000 0.000 0.000 0.000 0.000 5.000 0.000 fr 28.124 29.364 29.116 123.204 21.254 19.076 56.505 Conditional expression (1) |L0 / fr| 0.000 0.000 0.000 0.000 0.000 0.262 0.000 Conditional expression (2) Lst / Lm 1.510 1.507 1.522 1.501 1.518 1.001 1.868 Conditional expression (3) Lr / Lm 0.749 0.563 0.839 0.639 0.683 0.514 0.340 Conditional expression (4) |Lb / fr| 0.129 0.148 0.109 0.015 0.315 0.196 0.072 [Image display device 1] FIG. 16 shows the configuration of the image display device 1 using the display optical system 10 and the light guide 150 of Example 1. Note that, as the display optical system and the light guide, the display optical systems 20 to 70 and the light guides 250 to 750 of Examples 2 to 7 may be used.

[0080] The image display device 1 includes a light source device 801, illumination optical systems 802 and 803, a display element 804, a display control device 805, a display optical system 10, and a light guide 150. When a self-emitting display element is used as the display element 804, the light source device 801 and the illumination optical systems 802 and 803 may be omitted.

[0081] As the light source device 801, a solid light source such as an LED or a laser is suitable. As the illumination optical systems 802 and 803 for uniformly irradiating the illumination light from the light source device 801 onto the display element 804, a configuration in which the illumination light is multiply reflected in the light guide plate or the like can be adopted.

[0082] The display element 804 converts the uniformly irradiated illumination light into image light and makes it incident on the display optical system 10. As the display element 804, a DMD, a transmissive or reflective liquid crystal panel, an organic EL panel, or the like can be used. The display control device 805 controls at least one of the light source device 801 and the display element 804 based on the image information input from the outside. The display control device may be provided separately for the light source device 801 and the display element 804.

[0083] The light guide 150 is an eyepiece light guide that directly makes the image light incident on the eye of the observer OBS located on the observation side. The image light incident on the light guide 150 forms a pupil near the exit part of the light guide 150 while repeating reflections within the light guide 150, allowing the observer OBS to visually recognize the image. The reflection within the light guide 150 may be total internal reflection or may be due to a reflection film such as a dielectric film. The reflection member 806 provided on the light guide 150 is an element for reflecting and redirecting the image light incident on the light guide 150, and can be selected from optical elements such as a mirror, a diffractive optical element, a holographic element, a prism array, a metasurface, etc. according to the required reflection state within the light guide 150. The direction conversion member 807 provided on the light guide 150 redirects the image light so that the image light emitted from within the light guide 150 is incident on the eye (pupil) of the observer OBS. For the direction conversion member 807 as well, it may be appropriately selected from optical elements such as a diffractive optical element, a holographic element, a prism array, a metasurface, etc.

[0084] The configuration of the above image display device 1 is merely an example, and the display optical systems of Examples 1 to 7 may be used for image display devices having other configurations. [Image Display Device 2] FIG. 17 shows the configuration of an image display device 2 using any one of the display optical systems 10 to 70 of Examples 1 to 7. The image display device 2 is a glasses-type AR (Augmented Reality) display worn by the observer OBS.

[0085] The image display device 2 has a configuration in which display optical systems (10 to 70) for the right eye and the left eye and right-eye and left-eye lenses 902 as light guides are held in a frame 901. The display optical systems for the right eye and the left eye project image light onto the corresponding lenses 902, and the image light reflected by the lenses 902 is guided to the right eye and the left eye of an observer OBS located on the observation side, so that the observer OBS can visually recognize a display image 904.

[0086] Information acquisition devices 903 such as cameras are attached to the left and right sides of the frame 901. External brightness information, object information, etc. are acquired through the information acquisition device 903, and the display state such as the brightness of the display image 907 and the object display method is changed through an information control device 905 which is a computer. The information control device 905 may be built into the frame 901 or may be provided separately from the frame 901.

[0087] The display optical systems of the respective embodiments can be used in various image display devices such as an HMD (Head Mount Display) which is a non-glasses type display and an in-vehicle display device.

[0088] The above embodiments include the following configurations.

[0089] (Configuration 1) A refractive optical system having a positive refractive power, a reflective optical system having a refractive power, and an aperture stop, A display optical system that causes light emitted from a display surface to enter a light guide through the refractive optical system, the reflective optical system, and the aperture stop in this order, The aperture stop is arranged at a position closer to the light guide than the reflective optical system. A display optical system characterized by this. (Configuration 2) The reflective optical system has a positive refractive power. The display optical system according to Configuration 1, characterized by this. (Configuration 3) When the distance between the incident surface of the light guide and the aperture stop is L0 and the focal length of the refractive optical system is fr, |L0 / fr|≦0.3 The display optical system according to Configuration 1 or 2, characterized by satisfying the following conditions. (Configuration 4) Using the vertex of the surface closest to the reflective optical system in the refractive optical system as the first refraction point, the straight line passing through the first refraction point perpendicular to the display surface as the first axis, and the intersection point of the first axis and the reflective optical system as the reflection point, When the distance on the first axis between the first refraction point and the reflection point is Lm, and the minimum distance between the surface parallel to the display surface passing through the reflection point and the aperture stop is Lst, 1.0 ≦ Lst / Lm ≦ 2.2 The display optical system according to any one of Configurations 1 to 3, characterized by satisfying the following conditions. (Configuration 5) Using the vertex of the surface closest to the reflective optical system in the refractive optical system as the first refraction point, the straight line passing through the first refraction point perpendicular to the display surface as the first axis, and the intersection point of the first axis and the surface closest to the display surface in the refractive optical system as the second refraction point. When the distance between the first refraction point and the second refraction point on the first axis is Lr, 0.2 ≦ Lr / Lm ≦ 1.4 The display optical system according to any one of Configurations 1 to 4, characterized by satisfying the following conditions. (Configuration 6) Using the vertex of the surface closest to the reflective optical system in the refractive optical system as the first refraction point, the straight line passing through the first refraction point perpendicular to the display surface as the first axis, and the intersection point of the first axis and the surface closest to the display surface in the refractive optical system as the second refraction point, When the distance between the display surface and the second refraction point on the first axis is Lb, 0.005 ≦ |Lb / fr| ≦ 0.700 The display optical system according to any one of Configurations 1 to 5, characterized by satisfying the following conditions. (Configuration 7) The display optical system according to any one of Configurations 1 to 6, characterized in that the space between the refractive optical system and the reflective optical system is filled with air. (Configuration 8) The refractive optical system includes at least one positive lens and at least one negative lens, and is the display optical system according to any one of Configurations 1 to 7. (Configuration 9) The refractive optical system is composed of three lenses, and is the display optical system according to Configuration 8. (Configuration 10) The lens on the most reflection optical system side in the refractive optical system is a positive lens, and is the display optical system according to Configuration 8. (Configuration 11) The surface on the reflection optical system side of the lens on the most reflection optical system side in the refractive optical system is a convex surface, and is the display optical system according to Configuration 1. (Configuration 12) The display optical system is configured to make the image light pass through the aperture stop and enter the light guide so that the image light is emitted to the observation side through the light guide, and is the display optical system according to any one of Configurations 1 to 11. (Configuration 13) On the optical axis of the display optical system, the position of the aperture stop coincides with the position of the exit pupil of the light emitted from the display surface, and is the display optical system according to any one of Configurations 1 to 12. (Configuration 14) The display optical system according to any one of Configurations 1 to 13, and the light guide, and is an image display device.

[0090] Each of the above-described embodiments is merely a representative example, and various modifications and changes can be made to each embodiment when implementing the present invention.

Explanation of Reference Numerals

[0091] 10, 20, 30, 40, 50, 60, 70 Display optical system 110, 210, 310, 410, 510, 610, 710 Refractive optical system 101, 201, 301, 401, 501, 601, 701 Reflection optical system 120, 220, 320, 420, 520, 620, 720 Aperture stop 130, 230, 330, 430, 530, 630, 730 represent surfaces 150, 250, 350, 450, 550, 650, 750 light guides

Claims

1. A display optical system having a refractive optical system with a positive refractive power, a reflective optical system with a refractive power, and an aperture stop, wherein light emitted from a display surface is incident on a light guide through the refractive optical system, the reflective optical system, and the aperture stop in this order, and the aperture stop is disposed at a position closer to the light guide than the reflective optical system. The display optical system is characterized by this.

2. The reflective optical system has a positive refractive power. The display optical system according to claim 1 is characterized by this.

3. When the distance between the incident surface of the light guide and the aperture stop is L0 and the focal length of the refractive optical system is fr, |L0 / fr| ≤ 0.3 The display optical system according to claim 1 is characterized by satisfying the condition.

4. Taking the vertex of the surface closest to the reflective optical system in the refractive optical system as the first refraction point, the straight line passing through the first refraction point perpendicular to the display surface as the first axis, and the intersection point of the first axis and the reflective optical system as the reflection point, when the distance on the first axis between the first refraction point and the reflection point is Lm and the minimum distance between the surface parallel to the display surface passing through the reflection point and the aperture stop is Lst, 1.0 ≤ Lst / Lm ≤ 2.2 The display optical system according to claim 1 is characterized by satisfying the condition.

5. Taking the vertex of the surface closest to the reflective optical system in the refractive optical system as the first refraction point, the straight line passing through the first refraction point perpendicular to the display surface as the first axis, and the intersection point of the first axis and the surface closest to the display surface in the refractive optical system as the second refraction point, when the distance between the first refraction point and the second refraction point on the first axis is Lr, 0.2 ≤ Lr / Lm ≤ 1.4 The display optical system according to claim 1 is characterized by satisfying the condition.

6. Taking the vertex of the surface closest to the reflective optical system in the refractive optical system as the first refraction point, the straight line passing through the first refraction point perpendicular to the display surface as the first axis, and the intersection point of the first axis and the surface closest to the display surface in the refractive optical system as the second refraction point, when the distance between the display surface and the second refraction point on the first axis is Lb, 0.005 ≤ |Lb / fr| ≤ 0.700 The display optical system according to claim 1 is characterized by satisfying the condition.

7. The space between the refractive optical system and the reflective optical system is constituted by air. The display optical system according to claim 1 is characterized by this.

8. The refractive optical system according to claim 1, characterized in that it includes at least one positive lens and at least one negative lens

9. The display optical system according to claim 8, characterized in that the refractive optical system is composed of three lenses

10. The display optical system according to any one of claims 1 to 9, characterized in that the lens closest to the reflective optical system in the refractive optical system is a positive lens

11. The display optical system according to any one of claims 1 to 10, characterized in that the surface on the reflective optical system side of the lens closest to the reflective optical system in the refractive optical system is a convex surface

12. The display optical system according to claim 1, characterized in that the image light passing through the aperture stop is guided to the light guide so that the image light is emitted to the observation side through the light guide

13. The display optical system according to claim 1, characterized in that on the optical axis of the display optical system, the position of the aperture stop coincides with the position of the exit pupil of the light emitted from the display surface

14. A display optical system according to any one of claims 1 to 13 An image display device, characterized by comprising the light guide

Images