Optical unit, optical device, and image display system

Abstract

To reduce discomfort of an observer caused by contact with a device.SOLUTION: An optical unit (42) includes an optical system having a focus on the incident side of light on a position where a display image (Im) of an object is set, and emitting light from a focal plane as parallel light, and a housing part for housing the optical system, and has a constitution in which, when a visible area where the display image can be viewed is expressed as IB, IB≥7570 mm3 is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an optical unit, an optical device, and an image display system. [Background technology]

[0002] Various types of ophthalmic devices have been realized that enable observation of a subject's eye (hereinafter referred to as the subject's eye) for the purpose of eye diagnosis and surgical treatment in ophthalmology. As an example of an ophthalmic device, a surgical microscope is known that is configured so that the microscope can be freely moved relative to the subject's eye, improving the degree of freedom for the observer in observing the subject's eye (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-329762 A Summary of the Invention

[0004] A first aspect of the present disclosure is a method for manufacturing a semiconductor device comprising: an optical system having a focal point on a light incident side at a position where a display image of an object is set, and emitting light from the focal plane as parallel light; a housing portion that houses the optical system, If the visible area in which the display image can be viewed is IB, IB≧7570mm 3 The optical unit is configured to satisfy the condition expressed by the following formula:

[0005] A second aspect of the present disclosure is an optical system having a focal point on a light incident side at a position where a display image of an object is set, and emitting light from the focal plane as parallel light; the optical system includes a lens group including a first lens and a second lens, If the distance from the end of the first lens arranged on the incident side to the end of the second lens arranged on the exit side of the light is d1, and the distance from the position where the display image is set to the end of the second lens on the exit side of the light is d2, d1 / d2>0.5 The optical unit is configured to satisfy the condition expressed by the following formula:

[0006] A third aspect of the present disclosure is an optical system having a focal point on a light incident side at a position where a display image of an object is set, and emitting light from the focal plane as parallel light; the optical system includes a lens group including a first lens and a second lens, The optical system is an optical unit configured such that a principal ray of the maximum angle of view of the light of the display image passes through a position of a diameter larger than half the effective diameter of the first lens, on which the principal ray is incident.

[0007] A fourth aspect of the present disclosure is A plurality of the optical units An optical device comprising:

[0008] A fifth aspect of the present disclosure is a left optical system having a focal point on the light incident side at a position where a display image for the left eye is set as a display image of an object, emitting light from the focal plane as parallel light and forming a left eye visible area in which the display image for the left eye is visible; a right-side optical system having a focal point on a light incident side at a position where a right-eye display image different from the left-eye display image is set, emitting light from the focal plane as parallel light and forming a right-eye visible area in which the right-eye display image is visible; a housing portion that houses the left optical system and the right optical system; Equipped with In at least one of the left optical system and the right optical system, if the distance from the end of the lens surface on the light incident side to the end of the lens surface on the light exit side is d1 and the distance from the position of the display image to the end of the lens surface on the light exit side is d2, d1 / d2>0.5 Construct it so as to satisfy the conditional expression shown in It is an optical device.

[0009] A sixth aspect of the present disclosure is The optical device; An imaging unit that images the object; an arm unit on which the imaging unit is disposed; The image display system includes:

[0010] A seventh aspect of the present disclosure is An imaging unit that images an object; a plurality of optical devices, each of which is the optical device; a mounting unit that mounts each of the plurality of optical devices so as to be independently movable; The image display system includes: [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing an example of an overall configuration of an ophthalmologic system according to an embodiment. [Diagram 2] FIG. 1 is a conceptual diagram showing an example of a configuration of an image display device according to an embodiment. [Diagram 3] 3 is a conceptual diagram showing an example of a relationship between a lens on an observer side in an optical unit of an ophthalmologic system according to an embodiment and the observer's eye. FIG. [Figure 4] 1 is a conceptual diagram showing an example of a relationship between a lens in an optical unit of an ophthalmologic system according to an embodiment and an eye box region that depends on a half angle of view. [Diagram 5] 5 is a schematic diagram illustrating a relationship between a display unit and an optical unit in an ophthalmologic system according to an embodiment when an observer views the display unit with both eyes. FIG. [Figure 6] FIG. 4 is an explanatory diagram of an example of an end portion of a lens surface. [Figure 7] FIG. 4 is an explanatory diagram of an example of an end portion of a lens surface. [Figure 8] FIG. 4 is an explanatory diagram of an example of an end portion of a lens surface. [Figure 9A] FIG. 2 is a schematic diagram illustrating a configuration of an optical unit according to the embodiment. [Figure 9B] FIG. 4 is an enlarged view of the periphery of a pupil according to the embodiment. [Figure 10] FIG. 2 is a conceptual diagram showing a first example of a lens of an optical unit. [Figure 11] FIG. 13 is an image diagram showing a second example of a lens of the optical unit. [Figure 12] FIG. 11 is an image diagram showing a lens example 3 of the optical unit. [Figure 13] FIG. 11 is an image diagram showing a fourth example of a lens of the optical unit. [Figure 14] FIG. 11 is an image diagram showing a fifth example of a lens of the optical unit. [Figure 15] FIG. 11 is an image diagram showing a sixth example of a lens of the optical unit. [Figure 16] FIG. 13 is an image diagram showing a seventh lens example of the optical unit. [Figure 17] FIG. 11 is an image diagram showing lens example 8 of the optical unit. [Figure 18] FIG. 13 is an image diagram showing a lens example 9 of the optical unit. [Figure 19] 1 is a conceptual diagram showing an example of an exit pupil in a display device included in an ophthalmologic system according to an embodiment. [Figure 20] FIG. 2 is a conceptual diagram showing an example of a configuration of an optical unit. [Figure 21] FIG. 13 is a conceptual diagram illustrating an example of a suppression member according to the embodiment. [Figure 22] 13 is a conceptual diagram showing another example of a suppression member according to the embodiment. FIG. [Diagram 23] FIG. 13 is a conceptual diagram showing a modified example of the image display device in the ophthalmologic system according to the embodiment. [Figure 24] FIG. 1 is a conceptual diagram illustrating an example of an ophthalmologic system according to an embodiment. [Diagram 25] FIG. 1 is a conceptual diagram illustrating an example of an ophthalmologic system according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an example of an embodiment for implementing the technology of the present disclosure will be described with reference to the drawings. The present disclosure is applicable to any device that displays an image, and is also applicable to a system (e.g., an image display system) equipped with a device that displays an image. In this embodiment, in order to simplify the following description, a case in which the present disclosure is applied to an ophthalmic system in which an observer such as a doctor observes the eye (examined eye) of a patient or the like and the surroundings of the examined eye for the purpose of eye diagnosis (or examination) and surgical treatment (e.g., ophthalmic surgery) in ophthalmology will be described. Note that the same or equivalent components and parts are given the same reference symbols in each drawing. Also, the dimensional ratios of the drawings are exaggerated for the convenience of description and may differ from the actual ratios. Note that in this embodiment, the eye of a patient or the like is an example of an object.

[0013] The image display system according to the present disclosure is not limited to an ophthalmic system applied to an ophthalmic device. That is, it is not limited to an image display device that displays an image captured by an image capture device that captures an eye and the periphery of the eye for ophthalmology, but is applicable to an image display device (e.g., a medical image display device used for examination or surgery) that captures an object not limited to ophthalmology and displays the captured image, and an image display system. For example, in the field of medicine, it is also applicable to an image display device and an image display system used in any branch of medicine (e.g., neurosurgery). And, it goes without saying that the image display system according to the present disclosure is not limited to an image display device and an image display system used in any branch of medicine, but is applicable to an image display device and an image display system capable of displaying an image. In this specification, "ophthalmology" refers to a branch of medicine that deals with the eyes.

[0014] In addition, the image (display image) used in the image display system according to the present disclosure may be a still image or a moving image. In addition, the image used in the image display system according to the present disclosure is not limited to a captured image. In other words, using an image captured by a capture device as a captured image is an example of the present disclosure. For example, the present disclosure is also applicable to an image display device and an image display system that display an image prepared in advance.

[0015] An example of application of the ophthalmologic system described as an example of the image display system according to the present disclosure is a surgical image display system (e.g., a system including an ophthalmologic surgical microscope) used when an observer such as a doctor performs a procedure while observing the subject's eye and the surroundings of the subject's eye. The application of this ophthalmologic surgical microscope is also an example of the image display system according to the present disclosure, and in the medical field, it can also be applied to a surgical microscope used in any branch of medicine. It goes without saying that the image display system according to the present disclosure is not limited to a surgical microscope used in the medical field, and can be applied to other optical devices including a microscope for observing an object.

[0016] FIG. 1 illustrates an example of a configuration of an ophthalmologic system 10 according to an embodiment of the present disclosure. 1, the ophthalmologic system 10 includes an imaging unit 20 that images an eye to be examined and the periphery of the eye to be examined as an object OB, and an image display device 40 that displays the image captured by the imaging unit 20 for an observer OP. The image display device 40 includes a display unit 30 such as a liquid crystal or organic EL display that displays the image captured by the imaging unit 20, and an optical unit 42 that provides the image displayed on the display unit 30 for the observer OP. The image display device 40 in this embodiment is an example of an optical device including the display unit 30 and the optical unit 42.

[0017] In the image display device 40, a display section 30 such as a display is detachably attached to an optical unit 42. Also, an attachment mechanism 42P is provided in a portion of the light incident side of the optical unit 42, and the attachment mechanism 42P is an example of an attachment section for attaching and detaching the display section to the optical unit 42. The image display device 40 is formed by attaching the display section 30 to the optical unit 42. In the ophthalmologic system 10 according to this embodiment, the photographing section 20 and the image display device 40 including the display section 30 are formed independently, and the photographing section 20 and the image display device 40 are movable separately.

[0018] The ophthalmic system 10 according to the present embodiment will be described as an example in which an observer OP (e.g., a doctor, an assistant, a researcher, etc.) visually observes an object OB, that is, an eye (examined eye) and the periphery of the examined eye, with both eyes of the observer OP (binocular vision). An example of binocular vision is stereoscopic vision. The stereoscopic ophthalmic system 10 independently forms a right optical path of an image displayed for the right eye of the observer OP and a left optical path of an image displayed for the left eye. For example, the right optical path and the left optical path are arranged apart along a predetermined direction in correspondence with the left and right eyes of the observer OP and the interpupillary direction of the observer OP. Then, when viewed from the observer OP, the right optical path is arranged on the right side, and the left optical path is arranged on the left side. In the following description, when the right eye and the left eye are distinguished from each other, the components for the right eye are marked with R and the components for the left eye are marked with L, and when no distinction is necessary, the R and L symbols are omitted. In addition, in the following description, when the ophthalmic system 10 is installed on a horizontal plane, the interpupillary width direction of the observer OP is defined as the "Y direction," the direction perpendicular to the horizontal plane is defined as the "X direction," and the direction perpendicular to the X and Y directions, in which light travels toward the observer OP when the observer OP views an image of the object OB, is defined as the "Z direction."

[0019] The photographing unit 20 includes a microscope 22, a camera 24, and a camera controller 26. The microscope 22 includes an optical system for allowing an observer OP or the like to observe the subject's eye, which is an object OB, and the periphery of the subject's eye. The camera 24 is an electronic device that converts an image of the subject's eye, which is the object OB, and the periphery of the subject's eye captured by the microscope 22 into a video signal. The camera controller 26 is an electronic device that converts the video signal into a display signal. The camera controller 26 is connected to the display unit 30 and outputs the display signal to the display unit 30. As a result, the image captured by the camera 24 is formed on the display unit 30 as a captured image (display image) Im.

[0020] In this embodiment, in order to obtain an image to be displayed for the right eye and an image to be displayed for the left eye of the observer OP, the photographing unit 20 includes a photographing unit 20R for the right eye and a photographing unit 20L for the left eye. In detail, the photographing unit 20 includes a microscope 22R for the right eye and a microscope 22L for the left eye, and a camera 24R for the right eye and a camera 24L for the left eye. The controller 26 may be configured such that the controller 26R for the right eye and the controller 26L for the left eye are independent of each other, or may be configured as a single controller 26. When a single controller 26 is used, each of the video signals from the camera 24R for the right eye and the camera 24L for the left eye is image-processed, and the display signals for the right eye and the left eye after the image processing are output to a display unit 30R for the right eye and a display unit 30L for the left eye, which will be described later. The microscope 22 may be configured to form a parallax image (stereoscopic image) for stereoscopic vision by a single microscope, without including two microscopes (22R, 22L). Furthermore, when a stereoscopic image is not displayed, the microscope 22 can display a two-dimensional image of the object OB. The photographing unit 20 in this embodiment has the same configuration for each of the right eye and the left eye, and therefore individual descriptions are omitted.

[0021] Signal transmission and reception (e.g., sending and receiving image data) in the ophthalmologic system 10 according to this embodiment may be wireless or wired communication. For example, communication between the camera 24, the camera controller 26, and the display unit 30 may be wired or wireless communication. Note that the display unit 30 has the same configuration for each of the right and left eyes, and therefore individual explanations will be omitted. The observer OP operates the microscope 22 to set an observation position for the subject eye, which is the object OB, and the periphery of the subject eye.

[0022] The optical unit 42 included in the image display device 40 is an example of the optical unit of the present disclosure, and is an optical system that functions as an objective lens that at least refracts and emits light incident from the captured image Im (details will be described later). The optical unit 42 is an example of the optical system of the present disclosure, and has a focal point on the light incident side at a position where the captured image (display image) Im of the object is set, and emits light from the focal plane (in this case, the captured image Im, or the surface on which the captured image Im is placed) as parallel light. This optical unit 42 can include at least one doublet lens. The image display device 40 is attached to a base not shown, and is formed independently from the shooting unit 20 and is formed in a non-contact manner with respect to the observer OP. By forming the image display device 40 in a non-contact manner with respect to the observer OP, the discomfort of the observer OP caused by the observer OP contacting the image display device 40 is suppressed.

[0023] In the ophthalmologic system 10 according to the present embodiment, the photographing unit 20 and the image display device 40 are formed as separate bodies independent of each other, and each of them can be moved separately. Therefore, even if the observer OP moves the photographing unit 20 to change the observation position while visually observing the object OB (e.g., the subject's eye and the periphery of the subject's eye) on the image display device 40, the image display device 40 (e.g., the display unit 30) does not move, so the observer OP can visually observe the photographed image Im without moving his / her head. This is effective when an ophthalmic surgical microscope is applied to the photographing unit 20. For example, when performing a procedure while moving the surgical field, the observer OP, such as a doctor, can concentrate on the procedure while visually confirming the surgical field without changing the viewing position. In addition, by making the photographing unit 20 and the image display device 40 independent of each other, the photographing unit 20 only needs to be able to photograph the object OB, and the degree of freedom of the shape of the photographing unit itself is increased.

[0024] In addition, the ophthalmologic system 10 according to the present embodiment can prevent the observer OP from viewing the image display device 40 in an unnatural posture. For example, the observer OP can observe in an optimal position regardless of the observer's height. Moreover, the ophthalmic system 10 according to the present embodiment functions effectively when a plurality of observers OP, including an operator and an assistant, visually observe the object OB (for example, the eye to be examined and the periphery of the eye to be examined). That is, the ophthalmic system 10 according to the present embodiment includes at least a plurality of image display devices 40, and the photographing unit 20 and each of the plurality of image display devices 40 are formed independently and separately, and functions effectively when each separate observer OP visually observes the same photographed image or each photographed image of the object OB on each image display device 40. For example, the operator and the assistant are considered to visually observe the same part of the object OB while sitting on a chair or the like (seated position), but the operator is mainly responsible for identifying and moving the part to be visually observed on the object OB. However, when the ophthalmic system 10 is formed integrally, if the microscope or the like is moved when the operator identifies or moves the part to be visually observed, the assistant also needs to move along with the operator's movement. For example, when an operator moves a microscope or the like in the X direction (a direction away from the object OB) while observing an object OB, the unexpected movement may cause the assistant to come into contact with the eyepiece. On the other hand, in the ophthalmic system 10 according to the present embodiment, the imaging unit 20 and the image display device 40 are formed as independent and separate entities, and can move independently, so that the operator can concentrate on the procedure and the assistant can concentrate on the observation without having to worry about unexpected movements in the ophthalmic system 10.

[0025] FIG. 24 shows an example of the configuration of an ophthalmologic system including the image display device according to this embodiment. In the example shown in FIG. 24, the ophthalmologic system 10 displays a display image of an object OB (for example, an eye to be examined and the vicinity of the eye to be examined) captured by the imaging unit 20 on a 3D display device 30-1, which is a display, for an observer OP (here, referred to as a first user, the surgeon OP1) who is in a seated position and viewing the image while undergoing treatment. The 3D display device 30-1 displays a display image that presents a stereoscopic image to the surgeon OP1 using an image for the right eye (a display image for the right eye) and an image for the left eye (a display image for the left eye) of the object OB captured by the imaging unit 20 with parallax. Note that the present disclosure is not limited to stereoscopic display, and a two-dimensional image of the object OB captured by the imaging unit 20 may be displayed as is. In addition, the same display image as the display image viewed by the surgeon OP1 is displayed on a display unit 30 attached to the image display device 40 for another observer OP (here, referred to as a second user, the assistant OP2) who is in a seated position and viewing the image.

[0026] The imaging unit 20 is disposed on an arm 29A attached to a base 28, and can be freely moved by the operation of the surgeon OP1. The 3D display device 30-1 is installed in front of the surgeon OP1 (Y direction in FIG. 24) so ​​that its position can be adjusted. The image display device 40 is installed on an installation part 29B attached to the base 28 so as to be movable with the movement of the head of the assistant OP2, and can be freely moved in each direction of up, down, left, right, front, and back by the operation of the assistant OP2. This allows the imaging unit 20 and the image display device 40 to move independently. The arm 29A is an example of an arm of the present disclosure, the installation part 29B is an example of an installation part of the present disclosure, and the base 28 is an example of a base part to which the arm 29A and the installation part 29B are attached. In the example shown in FIG. 24, an example is shown in which the arm 29A and the installation part 29B are attached to the base 28, but the arm 29A and the installation part 29B may each be configured to be independent of a ground surface such as the ground.

[0027] In the example shown in FIG. 24, displays 30-2 and 30-3 different from the 3D display device 30-1 are arranged on the base unit 28. The displays 30-2 and 30-3 can display the same display image as the display image visually viewed by the surgeon OP1. For example, the display 30-2 can convert a display image for presenting a stereoscopic image to the surgeon OP1 into a two-dimensional image (for example, an image for the right eye or an image for the left eye) and display it, or can enlarge and display a part of the image displayed on the 3D display device 30-1. The display 30-3 can display a display image for presenting a stereoscopic image for the assistant OP2. The display 30-3 can display a display image to be presented to the surgeon OP1 or the assistant OP2 for another observer OP (here, referred to as a visitor OP3 as a third user).

[0028] In the ophthalmologic system 10 configured in this manner, the photographing unit 20 and the image display device 40 are formed as independent and separate entities, and can be moved independently of each other, allowing the surgeon to concentrate on the procedure and the assistant to concentrate on observation.

[0029] The 3D display device 30-1 may be installed via a base unit 28. In the example shown in Fig. 24, the display image is displayed to the surgeon OP1 by the 3D display device 30-1, and the display image is displayed to the assistant OP2 by the image display device 40, but the reverse may be true.

[0030] In addition, the positions of the surgeon OP1 and the assistant OP2 are not limited to the positions shown in FIG. 24. For example, when the patient is lying on his / her back and the operation is performed from the side of the patient's head as the object OB (temporal incision), the surgeon OP1 may be in the position of the assistant OP2 shown in FIG. 24, and the assistant OP2 may be in the position of the surgeon OP1 shown in FIG. 24. In this case, the surgeon OP1 may visually check the 3D display device 30-1, the position of which is adjusted in front of the surgeon OP1 (in the opposite direction to the Z direction in FIG. 24), or may visually check the display 30-3. Meanwhile, the image display device 40 that displays an image to the assistant OP2 can be freely moved by the operation of the assistant OP2, so the assistant OP2 may move the image display device 40 so that the assistant OP2 can visually check the image at the position of the surgeon OP1 shown in FIG. 24.

[0031] Furthermore, the observers OP viewing the image in the ophthalmologic system 10 are not limited to two, the surgeon OP1 and the assistant OP2. For example, there may be three or more observers. For example, consider a case where three people, one surgeon OP1 and two assistants OP2, perform the procedure. In this case, for example, the surgeon OP1 performs the procedure at the position of the surgeon OP1 shown in FIG. 24, and the two assistants OP2 assist the surgeon OP1 at both sides. In this case, the surgeon OP1 performs the procedure while viewing the 3D display device 30-1, which is the front monitor, the assistant OP2 at the position shown in FIG. 24 views the display 30-3 or the image display device 40, and the assistant at the opposite side to the assistant OP2 at the position shown in FIG. 24 views the image display device 40.

[0032] FIG. 25 shows another example of the configuration of an ophthalmologic system including the image display device according to this embodiment. In the example shown in FIG. 25, the ophthalmologic system 10 includes a plurality of image display devices 40-1 and 40-2. The image display device 40-1 displays a display image for the surgeon OP1, and the image display device 40-2 displays a display image for the assistant OP2. The photographing unit 20 is disposed on an arm unit 29A attached to a base unit 28, and can be freely moved by the operation of the surgeon OP1. In the example shown in FIG. 25, the image display devices 40-1 and 40-2 are disposed for each of the surgeon OP1 and the assistant OP2. The image display device 40-1 is disposed on a mounting unit 29C attached to the base unit 28 so as to be movable in accordance with the movement of the head of the surgeon OP1, and can be freely moved in each of the directions of up, down, left, right, front and back by the operation of the surgeon OP1. In addition, the image display device 40-2 is disposed on a mounting unit 29B attached to the base unit 28 so as to be movable in accordance with the movement of the head of the assistant OP2, and can be freely moved in each of the directions of up, down, left, right, front and back by the operation of the assistant OP2. As a result, the photographing unit 20 and the image display devices 40-1 and 40-2 can be moved independently. Furthermore, each of the image display devices 40-1 and 40-2 can be moved independently. In this way, the photographing unit 20 and the image display devices 40 (in this case, the image display devices 40-1 and 40-2) are formed as independent and separate bodies and can be moved independently, so that the surgeon can concentrate on the treatment and the assistant can concentrate on the observation. In the example shown in FIG. 25, an example is shown in which the arm unit 29A, the installation unit 29B, and the installation unit 29C are attached to the base unit 28, but the arm unit 29A, the installation unit 29B, and the installation unit 29C may each be configured to be independent from a contact surface such as the ground.

[0033] FIG. 2 shows an example of the configuration of the image display device 40. Note that FIG. 2 shows the image display device 40 in a top view, and shows an example in which independent optical units 42 are arranged for the right eye and the left eye of the observer OP. The optical unit 42 includes an optical unit 42R for the right eye, which is an example of a right optical system, and an optical unit 42L for the left eye, which is an example of a left optical system. The optical unit 42R for the right eye and the optical unit 42L for the left eye are arranged along a direction corresponding to the interpupillary direction of both eyes of the observer OP (for example, the Y direction in FIG. 2). Note that the optical unit 42R for the right eye and the optical unit 42L for the left eye may be arranged along a direction corresponding to the parallax direction in which the observer OP wants to provide parallax. For example, the optical unit 42R for the right eye and the optical unit 42L for the left eye are arranged apart from each other along a predetermined direction in correspondence with the left and right eyes of the observer OP and the interpupillary direction of the observer OP. When viewed from the observer OP, the right-eye optical unit 42R is disposed on the right side, and the left-eye optical unit 42L is disposed on the left side. The right-eye optical unit 42R includes a right-eye display unit 30R on the right-eye optical unit 42R and a right-side mounting mechanism 42PR as an example of a mounting portion on the light incident side of the right-eye optical unit 42R, and the left-eye optical unit 42L includes a left-eye display unit 30L on the left-eye optical unit 42L and a left-side mounting mechanism 42PL as an example of a mounting portion on the light incident side of the left-eye optical unit 42L.

[0034] As shown in Fig. 2, the image display device 40 forms an image (a right-eye display image, which is an example of a right-side display image) by the right-eye photographing unit 20R, which is an example of a right-side photographing unit, on the display unit 30R as a photographed image ImR, and provides it to the right eye of the observer OP via the right-eye optical unit 42R. Also, an image (a left-eye display image, which is an example of a left-side display image) by the left-eye photographing unit 20L, which is an example of a left-side photographing unit, is formed on the display unit 30L as a photographed image ImL, and provides it to the left eye of the observer OP via the left-eye optical unit 42L. The right-eye optical unit 42R and the left-eye optical unit 42L are accommodated in a housing case 41 that blocks external light (e.g., noise light) incident from a source other than the optical path of the optical unit 42. The storage case 41 is an example of a storage section that stores and fixes the right-eye optical unit 42R and the left-eye optical unit 42L, and can fix the right-eye optical unit 42R and the left-eye optical unit 42L so that their optical axes are parallel to each other. The storage case 41 may be composed of a first storage case that stores the right-eye optical unit 42R and the left-eye optical unit 42L independently, and a second storage case that stores the first storage case.

[0035] Further, the optical unit 42R for the right eye and the optical unit 42L for the left eye of the image display device 40 have pupils. That is, the optical unit 42R and the optical unit 42L for the left eye form pupils on the light exit side. The pupils have an entrance pupil and an exit pupil, and the image display device 40 forms an entrance pupil InpR for the right eye of the right optical system and an entrance pupil InpL for the left eye of the left optical system on the light exit side of the image display device 40 in the optical path outside the optical system, that is, in front of the observer OP. In the following description, the entrance pupil InpR for the right eye and the entrance pupil InpL for the left eye are collectively referred to as "entrance pupil Inp" when there is no need to distinguish between the left and right (see FIG. 9A and FIG. 9B). Further, the image display device 40 forms an exit pupil ExpR for the right eye and an exit pupil ExpL for the left eye on the light exit side of the image display device 40 in the optical path outside the optical system, that is, in front of the observer OP. In the following description, the right eye exit pupil ExpR and the left eye exit pupil ExpL will be collectively referred to as "exit pupil Exp" when there is no need to distinguish between the left and right (see FIGS. 9A and 9B).

[0036] The ophthalmologic system 10 of this embodiment displays a captured image ImR for the right eye and a captured image ImL for the left eye, which differ depending on the parallax, in space (e.g., a visible area described below), and allows an observer OP to view the object OB as a three-dimensional image by viewing it with his or her right and left eyes.

[0037] Here, the image display device 40 formed independently of the photographing unit 20 and formed in non-contact with the observer OP can suppress the discomfort of the observer OP caused by the contact of the image display device 40 with the distance from the observer OP. However, generally, as the image display device 40 and the observer OP are separated, the photographed image Im visible to the observer OP becomes smaller. That is, the photographed image Im is visible within a range that encompasses the entire angle of view of the light emitted from the optical unit 42, known as the so-called eye point. On the other hand, when the viewing position of the observer OP deviates from the eye point, at least a part of the light of the angle of view of the light emitted from the optical unit 42 does not reach the observer OP. In this case, a state occurs in which the light of at least a part of the angle of view is blocked, and the observer OP cannot see the entire image of the object OB. Therefore, by increasing the eye point, it is possible to contribute to suppressing and improving the discomfort of the observer OP caused by the contact of the observer OP with the image display device 40, or to expanding the observation area in which the appearance of the image does not change. Therefore, in this embodiment, an optical unit 42 that can increase the eye point is provided.

[0038] The light emitted from the optical unit 42 is a light flux that is rotationally symmetrical about the optical axis of the optical unit 42. Therefore, the range that is visible covering the entire angle of view of the light emitted from the optical unit 42, which is the eye point, is a substantially conical area with the optical axis of the optical unit 42 as its axis. In this embodiment, the substantially conical area with the optical axis of the optical unit 42 as its axis, which is the range that is visible covering the entire angle of view of the light emitted from the optical unit 42, is called the eyebox area. For example, the eyebox area is a visible area formed on the light emission side of the optical unit 42 (or in front of the observer OP) and formed by a group of positions where an image can be viewed in a predetermined space. The eyebox area also includes an area where the appearance of the displayed image (in this case, the captured image Im) does not change if it is within the area when the eyes of the observer OP are placed in the space. When the optical unit 42 is configured with an afocal optical system described later, the appearance of the displayed image is, for example, the size of the image. Furthermore, the eyebox region includes an area within which the observation range does not change when the eyes are positioned in space.

[0039] The eyebox region, which is a visible region where the display image can be viewed by the observer OP, can be derived based on the lens system included in the optical unit 42 and the angle between the chief ray of the maximum angle of view and the optical axis of the optical unit 42. Note that the chief ray of the maximum angle of view is the chief ray emitted from the maximum object height of the display image, and is also the chief ray of the projection angle.

[0040] FIG. 3 shows the relationship between the lens Le arranged on the observer side among the lens group of the optical unit 42 and the eyes of the observer OP. As shown in FIG. 3, the half angle of view (the angle between the principal ray of the maximum angle of view and the optical axis) is ω (hereinafter, sometimes referred to as the angle of view), the eye relief is ER, and the eye point diameter is φ EP , a visible area (hereinafter referred to as eyebox area) IB in which the viewer OP can view the display image, which is the eyebox area, can be expressed by the following equation. IB = {(φ EP / 2) / tanω+ER}·{(φ EP / 2) + ER tanω} 2 π(1 / 3)

[0041] The half angle of view ω is the angle between the optical axis CL and a ray of light reaching the eye of the observer OP from the lens Le of the optical unit 42 that is closest to the eye of the observer OP in the lens group of the optical unit 42 (for example, the lens located on the outermost surface on the light exit side of the optical unit 42). The eye relief ER is the distance from the vertex of the lens Le to the vertex (eye point) of the assumed eye of the observer OP. The eye point diameter φ EP is the length of the area where light rays of all angles emitted from the lens Le reach the eyes of the observer OP when the observer OP moves his / her eyes in one direction (for example, up and down) at the eye relief ER position.

[0042] The effective diameter of the lens Le of the optical unit 42 closest to the eye of the observer OP is φ LS Then, the eye box area IB can also be expressed by the following equation: IB=(π / 3)·(φ LS / 2) 2 ·{(φ LS / 2) / tanω}

[0043] Here, the effective diameter φ of the lens of the lens group of the optical unit 42 on the eye side of the observer OP is LS and the half angle of view ω of the light emitted from the optical unit 42 will be described.

[0044] Fig. 4 shows an example of the relationship between the effective diameter φLS of the lens on the eye side of the observer OP and the eyebox area IB, which depends on the half angle of view ω of the light emitted from the optical unit 42. In Fig. 4, the half angle of view (ω) indicating the angle between the optical axis CL of the optical unit 42 and the light emitted from the optical unit 42 is used as the angle of view ω.

[0045] As shown in FIG. 4, for example, 10,000 mm 3 In order to obtain the eye box area IB, the curve Cv1 shown in Figure 4 is set as the boundary, and the area is set to 10,000 mm 3The effective diameter φ of the eye box area IB is LS and half angle of view ω (in the example shown in FIG. 4, the curve Cv1 is the boundary and the optical unit 42 is included in an area AR-Y that indicates the right side area in the figure). On the other hand, in the example shown in FIG. 4, the optical unit 42 is included in an area AR-X that indicates the left side area in the figure with the curve Cv1 as the boundary, and the 10000 mm 3 It is difficult to obtain an eye box area IB of 20,000 mm or more. 3 In order to obtain the eye box area IB, the curve Cv3 shown in Figure 4 is set as the boundary, and the area is set to 20,000 mm 3 The effective diameter φ of the eye box area IB is LS and the half angle of view ω (in the example shown in FIG. 4, the relationship is such that the optical unit 42 is included in an area AR-Y that indicates the right side area in the figure with the curve Cv3 as the boundary). 3 In order to obtain the eye box area IB above, the curve Cv4 shown in Figure 4 is used as the boundary, and the area is 30,000 mm 3 The effective diameter φ of the eye box area IB is LS and the half angle of view ω (in the example shown in FIG. 4, the relationship is such that the half angle of view is included in an area AR-Y that indicates the right side area in the drawing with the curve Cv4 as the boundary), and 3 In order to obtain the eye box area IB above, the curve Cv5 shown in Figure 4 is used as the boundary, and the area is 40,000 mm 3 The effective diameter φ of the eye box area IB is LS and the half angle of view ω (in the example shown in FIG. 4, the relationship is such that the optical unit 42 is included in an area AR-Y that indicates the right-hand region in the figure with the curve Cv5 as the boundary).

[0046] Next, the effective diameter φ of the lens on the observer's eye side LS and the half angle of view ω of the light emitted from the optical unit 42 will be considered.

[0047] In the ophthalmologic system 10 according to this embodiment, the observer OP views the object OB with both eyes, so the distance between the optical axis of the optical unit 42L for the left eye and the optical axis of the optical unit 42R for the right eye corresponds to the pupil distance PD between the two eyes, which is the interpupillary distance of the observer OP. The pupil distance PD of a human being is statistically distributed in the range of 41 mm to 73 mm. Therefore, considering the pupil distance PD to be 57 mm, which is the median value, and assuming the pupil diameter to be 2 mm as the standard, the eyepoint diameter φ EP If the eyeball diameter is set to the standard 24 mm and the eye is visible within a range of 30 degrees of rotation, the eyepoint diameter φ EP If the effective diameter φ of the lens on the eye side of the observer OP is set to 30 mm, light will be incident on almost all of the observer's OP eyes. Also, considering that the eyelashes of the observer OP will come into contact with the lens on the eye side, it is preferable that the eye relief ER is 15 mm or more. The half angle of view of the eyepiece lens of a standard microscope is 20 degrees. From the above, the effective diameter φ of the lens on the eye side of the observer OP is set to 15 mm or more. LS It is preferable that the minimum value be 41 mm.

[0048] In addition, when an area with low information discrimination ability but affecting a subjective spatial coordinate system is assumed as the visual field, for example, when a visual field that creates a sense of immersion is assumed, it is preferable to set the half angle of view to ±50 degrees or less. Setting the half angle of view to ±50 degrees or less can cover the induced visual field, which is known as an area that affects the subjective spatial coordinate system. In addition, when a stable fixation visual field, which is known as an area where one can gaze effortlessly with eye and head movement and can effectively receive information, is assumed, it is preferable to set the half angle of view to ±45 degrees or less. Furthermore, when an effective visual field, which is known as an area where information can be instantly received only by eye movement, is assumed, it is sufficient that the half angle of view includes at least ±15 degrees. Furthermore, when a discrimination visual field, which is known as a central vision area with excellent visual functions such as visual acuity, is assumed, it is sufficient that the half angle of view includes at least ±2.5 degrees.

[0049] Therefore, when the induced visual field is assumed as described above, it is preferable to set the half angle of view ω to ±50 degrees or less. That is, the eye box area IB is ω≦50 degrees It is preferable to configure the optical unit 42 so as to satisfy the condition expressed by:

[0050] In this case, the effective diameter φ of the lens on the eye side of the observer OP LS The eye box area IB formed by the light emitted by the optical unit 42 having a focal length of 41 mm and a half angle of view ω of 50 degrees is calculated by adding φ LS Substituting =41 and ω=50, it is about 7570 mm 3 (For example, the intersection point ST in Figure 4). This results in an eye box area IB of 7570 mm 3 If the optical unit 42 is configured as described above, the image display device 40 can be formed in such a way that almost all observers OP can view the displayed image (for example, a photographed image) by the induced visual field, and the observers OP do not come into contact with the optical unit 42. For example, as shown in FIG. 3 In order to obtain the eye box area IB, the curve Cv2 shown in Figure 4 is used as the boundary, and the area is 7570 mm 3 The effective diameter φ of the eye box area IB is LS and the half angle of view ω (in the example shown in FIG. 4, the relationship is such that the optical unit 42 is included in an area AR-Y that indicates the right-hand region in the figure with the curve Cv2 as the boundary).

[0051] For the above reasons, it is preferable that the optical unit 42 in this embodiment is formed using the following design conditions. The first design condition is that the eye box area IB is: IB≧7570mm 3 The optical unit 42 (the optical unit 42R and the optical unit 42L) is configured so as to satisfy the first conditional expression represented by:

[0052] In addition, for example, assuming an adult interpupillary distance PD, the effective diameter φ of the lens on the eye side of the observer OP in the first design condition described above is LS can be set to 53.5 mm or more, and the 7570 mm in the first conditional expression 3 is 16800mm3 It is possible to replace it with. That is, the eye box area IB is IB≧16800mm 3 It is also possible to configure the optical unit 42 so as to satisfy the expanded first conditional expression expressed as follows:

[0053] In addition, when a stable fixation field is assumed as described above, it is preferable that the half angle of view is set to ±45 degrees or less. In this case, the effective diameter φ of the lens on the eye side of the observer OP is LS The eye box area IB formed by the light emitted by the optical unit 42 having a focal length of 41 mm and a half angle of view ω of 45 degrees is calculated by adding φ LS Substituting =41 and ω=45, we get about 9000 mm 3 This makes the eye box area IB 9000mm 3 By configuring the optical unit 42 as described above, an image display device 40 can be formed in which almost all observers OP can view the displayed image (e.g., a photographed image) with a stable field of view, without the observers OP coming into contact with the optical unit 42.

[0054] For the above reasons, when a stable fixation field is assumed, the optical unit 42 in this embodiment is preferably formed using the following design conditions. The first design condition is that the eye box area IB is: IB≧9000mm 3 The optical unit 42 (the optical unit 42R and the optical unit 42L) may be configured so as to satisfy the first conditional expression expressed as follows:

[0055] In addition, for example, assuming a stable visual field and an adult interpupillary distance PD, the effective diameter φ of the lens on the eye side of the observer OP is LS can be set to 53.5 mm or more, and the 9000 mm in the first conditional expression 3 is 20000mm 3 It is possible to replace it with. That is, the eye box area IB is IB≧20000mm 3 It is also possible to configure the optical unit 42 so as to satisfy the expanded first conditional expression expressed as follows:

[0056] By the way, the half angle of view ω of a typical microscope is 20 degrees or more, and the effective diameter φ of the lens on the eye side of the observer OP is LS When the focal length is 41 mm, the eye box area IB formed by the light emitted by the optical unit 42 is calculated by adding φ LS Substituting =41 and ω=20, it comes to about 24,800 mm. 3 This results in an eye box area IB of 24800 mm. 3 If the optical unit 42 is configured as described above, it is possible to form an image display device 40 in which almost all observers OP can view a displayed image (e.g., a photographed image) while ensuring a field of view equivalent to that of a general microscope, and in which the observer OP does not come into contact with the optical unit 42. Furthermore, assuming an interpupillary distance PD of an adult, the effective diameter φ of the lens on the eye side of the observer OP can be set to LS If the focal length is 53.5 mm, the eye box area IB is 55000 mm according to the above formula. 3 become.

[0057] Therefore, the eye box area IB is IB≧24800mm 3 It is also possible to configure the optical unit 42 so as to satisfy the further expanded first conditional expression expressed as follows: Also, preferably, the eye box region IB is IB≧55000mm 3 It is also possible to configure the optical unit 42 so as to satisfy the expanded first conditional expression expressed as follows:

[0058] Here, without changing the half angle of view (ω=20 in this case), the effective diameter φ of the lens on the eye side of the observer OP is changed. LS The presence or absence of eye rotation is considered in the above discussion. Eye rotation includes the range of movement of the eye due to eye movement. When the rotation is visible within a range of ±15 degrees, the effective diameter φ LS is 35.2mm, and the eye box area IB is 15700mm 3 In this way, assuming a rotation of ±15 degrees, and taking into account the degree of freedom of the observer's head, the eye box area IB is 15,700 mm 3 The above is preferred. Therefore, the eye box area IB is IB≧15700mm 3 It is also possible to configure the optical unit 42 so as to satisfy the expanded first conditional expression expressed as follows: In addition, when the rotation is visible within a range of ±20 degrees, the effective diameter φ LS is 37.2mm, and the eye box area IB is 18500mm 3 In addition, if the rotation is visible within a range of ±30 degrees, the effective diameter φ LS is 41mm, and the eye box area IB is 24800mm 3 Therefore, the eye box area IB is 15700 mm 3 The above conditions are included.

[0059] In the case of an optical instrument such as a microscope used by an observer OP, the viewing angle is 11 degrees or more. Assuming a standard interpupillary distance PD, the effective diameter φ of the lens on the eye side of the observer OP is LS It is preferable to allow a size of about 65 mm. In this case, the eye box area IB is 185,000 mm 3 It is believed that the functions of the image display device 40 of the present disclosure can be achieved by allowing a size up to that level. That is, the eye box area IB is IB≦185000mm 3 It is preferable to configure the optical unit 42 so as to satisfy the conditional expression indicating the upper limit value given by:

[0060] By the way, the statistically average interpupillary distance PD is 65 mm. This means that the effective diameter φ LSIt is preferable that the maximum value be 65 mm. The second design condition is the effective diameter φ of the lens on the eye side of the observer OP. LS but, φ LS ≦65mm The optical unit 42 is configured so as to satisfy the second conditional expression:

[0061] As described above, the effective diameter φ of the lens on the eye side of the observer OP LS It is preferable to have a minimum value of 41 mm. The third design condition is the effective diameter φ of the lens on the eye side of the observer OP. LS but, φ LS ≧41mm The optical unit 42 is configured so as to satisfy the third conditional expression:

[0062] In addition, the pupil distance PD or the effective diameter of the lens φ LS In this case, the eye box region IB is preferably formed in a large area. 3 In order to obtain the eyebox area IB, the effective diameter φ is set so as to be included in the area AR-Y, which shows the right side area in FIG. 4, with the curve Cv1 as the boundary. LS The optical unit 42 may be formed so that the relationship between the half angle of view ω and the focal length φ is satisfied. 3 In order to obtain the eyebox area IB, the effective diameter φ must be set so that it is included in the area AR-Y, which is the right-hand area in FIG. 4, with the curve Cv3 as the boundary. LS The optical unit 42 may be formed so that the relationship between the half angle of view ω and the focal length ω is 30,000 mm. 3 In order to obtain the eyebox area IB, the effective diameter φ must be set so that it is included in the area AR-Y, which is the right-hand area in FIG. 4, with the curve Cv4 as the boundary. LS and the half angle of view ω, 40,000 mm. 3 In order to obtain the eyebox area IB, the effective diameter φ must be set so that it is included in the area AR-Y, which is the right-hand area in FIG. 4, with the curve Cv5 as the boundary. LSand the half angle of view ω.

[0063] The eyebox region IB, which is the visible region, can be derived based on the effective diameter of the lenses included in the optical unit 42 (the optical unit 42R for the right eye and the optical unit 42L for the left eye) and the angle between the chief ray of the maximum angle of view and the optical axis of each of the optical units 42 (the optical unit 42R for the right eye and the optical unit 42L for the left eye). In this case, it is preferable that the eyebox region IB, which is the visible region, is formed so that the half angle of view ω satisfies the condition of 50 degrees or less (ω≦50).

[0064] Fig. 5 shows a schematic diagram of the relationship between the display unit 30 and the optical unit 42 when an observer OP views the display unit 30 with both eyes. Since the relationship between the optical paths of the left and right eyes is the same, Fig. 5 describes the relationship between the optical path of the right eye eyeR, which is an example of the right-side optical path, by adding symbols, and omits the description of the relationship between the optical path of the left eye eyeL, which is an example of the left-side optical path.

[0065] Considering that the interpupillary distance PD of the observer OP is typically 60 mm to 70 mm, the maximum diameter of the inscribed circle MD of the display unit 30 corresponding to the optical paths of the left and right eyes when viewing an object with both eyes is 60 mm to 70 mm. Here, it is known that the off-axis light has asymmetric aberration that does not exist in the axial light. However, for example, when a lens is arranged in a region where the axial light and the off-axis light overlap, it is difficult to correct the aberration specific to the off-axis light with the arranged lens. Therefore, as shown in FIG. 5 of this embodiment, the aberration can be corrected by arranging a lens of the optical unit 42 (for example, a lens Lf shown in FIG. 9A described later) in a region where the axial light (for example, the chief ray of the axial light) and the off-axis light (for example, the chief ray of the off-axis light) do not overlap and the light ray interval between the axial light and the off-axis light is wide. Also, as shown in FIG. 5, the axial light JI and the off-axis light JE are separated from the lens surface of the optical unit 42 as they approach the display unit 30. Taking these matters into consideration, various experiments were conducted to investigate the enlargement of the eyebox area, and as a result, it was found that by making the distance from the lens surface of the optical unit 42 closest to the eye (for example, the eye-side lens surface of lens Le shown in FIG. 9A described later) to the end of the lens surface closest to the display unit 30 (for example, the lens surface of lens Lf shown in FIG. 9A described later) twice the distance d1, which is greater than the distance d2 from the lens surface closest to the eye to the display unit 30, the optical unit 42 is capable of correcting at least one of the coma aberration of off-axis light, the chromatic aberration of magnification, and the distortion without worsening the aberration of on-axis light, even when the eyebox area is enlarged.

[0066] Therefore, the fourth design condition is: As described above, when the distance from the lens surface closest to the eye of the observer OP arranged in a space (for example, an eye box region) to the end of the lens surface closest to the display unit 30 is d1, and the distance from the lens surface closest to the eye of the observer OP to the display unit 30 is d2, d1 / d2>0.5 The optical unit 42 is configured so as to satisfy the fourth conditional expression expressed as follows: In this case, it is assumed that the eye relief is 20 mm.

[0067] Therefore, by configuring the optical unit 42 so as to satisfy the fourth conditional formula under the fourth design condition, even if the eyebox area formed by the optical unit 42 is enlarged, it is possible to correct the coma aberration, lateral chromatic aberration, and distortion of off-axial light without worsening the aberration of on-axial light.

[0068] The image display device according to this embodiment has a focal point on the light incident side at a position where a display image for the left eye is set as a display image of an object, and emits light from the focal plane as parallel light to form a left-eye visible area in which the display image for the left eye is visible. An optical unit 42L for the left eye as a left optical system. an optical unit 42R for a right eye as a right optical system having a focal point on the light incident side at a position where a display image for a right eye different from the display image for the left eye is set, emitting light from the focal plane as parallel light, and forming a right-eye visible area in which the display image for the right eye is visible; a housing case 41 as a housing portion for housing the left optical system and the right optical system; Equipped with In at least one of the left optical system and the right optical system, if the distance from the end of the lens surface on the light incident side to the end of the lens surface on the light exit side is d1 and the distance from the position of the display image to the end of the lens surface on the light exit side is d2, d1 / d2>0.5 It is possible to configure the device so as to satisfy the conditional expression shown below.

[0069] Note that, since it becomes difficult to configure the image display device 40 of the present disclosure when the distance d1 exceeds the distance d2, the upper limit value of the value of (d1 / d2) in the fourth conditional expression is "1". 1>d1 / d2>0.5 It is preferable to configure the optical unit 42 so as to satisfy the fourth conditional expression given below, which defines an upper limit value.

[0070] Here, the end of the lens surface, which is the starting point of the above distances d1 and d2, varies depending on the shape of the lens surface. In this embodiment, the end of the lens surface is a plane perpendicular to the optical axis and in which only the vertices of the lens surface are in contact. For example, the end of the lens surface of the optical unit 42 closest to the display unit 30 refers to the portion of the optical unit 42 that protrudes the most toward the display unit 30 in the optical axis direction.

[0071] 6 to 8 show the end of lens surfaces of various shapes. FIG. 6 shows the end of the lens surface of lens Lf1 having a convex surface, FIG. 7 shows the end of the lens surface of lens Lf2 having a concave surface, and FIG. 8 shows the end of the lens surface of lens Lf3 having an aspheric surface. As shown in FIG. 6, in the case of a convex surface, it is the part that coincides with the position where the optical axis and the lens surface intersect, and as shown in FIG. 7, in the case of a concave surface, it is the edge part of the lens. As shown in FIG. 8, in the case of an aspheric surface, it is the part that protrudes most toward the display unit 30 in the optical axis direction.

[0072] Incidentally, when an observer OP views a captured image Im with both eyes, such as in stereoscopic vision, it is preferable to display the left and right images separately in accordance with the interpupillary distance PD between the observer OP's eyes. For this reason, it is preferable that the lens diameter of each of the optical units 42R and 42L is equal to or smaller than the interpupillary distance PD. For example, when an observer with an interpupillary distance PD of 65 mm is taken as the standard, it is preferable that the lens diameter of each of the optical units 42R and 42L is equal to or smaller than 65 mm. For this reason, it is preferable to form the optical unit 42 using the following fifth and sixth design conditions.

[0073] The fifth design condition is: Let f be the focal length of the optical unit 42, D be the distance of the captured image Im displayed by the display unit 30 (for example, the distance or size indicating the diameter of the inscribed circle, the diameter of the circumscribed circle, the lengths of the sides and diagonals, etc. of the image display area), and θ be the projection angle of light from the optical axis of the optical unit 42. f≦(D / 2) / sinθ The object of the present invention is to form the optical unit 42 so as to have a focal length of 100 mm or less so as to satisfy the fifth conditional expression:

[0074] It is preferable to set the distance D of the captured image Im to a distance equal to or greater than the length of the shortest straight line passing through the center of the captured image Im on the captured image Im to be displayed. In this case, the distance D of the captured image Im is the length or size of the image display area of ​​the display unit 30, and includes a distance equal to or greater than the length of the straight line passing through the center of the area (or image) in the image display area. For example, if the captured image Im is circular, the diameter is set as the distance D. Also, if the captured image Im is elliptical, the minor axis is set as the distance D. The center of the captured image Im may be the optical axis, the visual axis viewed by the observer, or any position within the captured image Im.

[0075] By using the fifth design condition, the optical unit 42 can be formed in consideration of the constraints on the size of the captured image Im displayed on the display unit 30 and the constraints on the projection angle of light from the optical axis of the optical unit 42. For example, if the distance of the captured image Im is set to a predetermined value of 65 mm or less, which is determined by the interpupillary distance PD in binocular vision, and the projection angle θ is set to be equal to or greater than that of a standard eyepiece with a magnification of 10x and a field number of 18, then the focal length f will be 100 mm or less. The projection angle θ corresponds to the half angle of view ω.

[0076] The sixth design condition is: Let f be the focal length of the optical unit 42, S be the size of the pixels (pixel size) constituting the captured image Im displayed on the display unit 30, and R be the resolution of the eye. f ≧ S / tan R The objective of the present invention is to form the optical unit 42 so as to have a focal length of 25 mm or more so as to satisfy the sixth conditional expression:

[0077] By using the sixth design condition, the optical unit 42 can be formed in consideration of the constraints on the size of the pixels constituting the captured image Im by the display unit 30 and the constraints on the resolution of the eye. That is, it is possible to suppress degradation of the image quality of the captured image Im, which is perceived as the size of the pixels constituting the captured image Im due to the resolution of the eye. For example, when the size (pixel size) S of the pixels constituting the captured image Im by the display unit 30 is 15 μm or more and the resolution R of the eye is 2 arc minutes or less, the focal length f is 25 mm or more.

[0078] From these fifth and sixth design conditions, when a captured image Im is formed by a display unit 30 with a pixel size S of 15 μm or more for an observer OP with an interpupillary distance PD of 65 mm, it is preferable that the focal length f of the optical unit 42 is 25 mm or more and 100 mm or less. By setting the focal length f of the optical unit 42 to 25 mm or more and 100 mm or less, the image display device 40 can improve image quality by suppressing the sense of roughness in the image caused by visual discrimination of individual pixels while maintaining the half angle of view.

[0079] As described above, when a lens is arranged in a region where the axial light JI and the off-axial light JE (see FIG. 5) overlap, it is difficult to correct the aberration specific to the off-axial light JE with the arranged lens. For this reason, it is desirable that the axial light JI (e.g., the chief ray of the axial light) and the off-axial light JE (e.g., the chief ray of the off-axial light) do not overlap as much as possible on the lens surface on the light incident side, and the ray interval between the chief ray of the axial light JI and the chief ray of the off-axial light JE is more separated. That is, it is preferable to configure the optical unit 42 so that the ray interval is such that the chief ray of the axial light and the chief ray of the off-axial light do not overlap on the lens surface on the light incident side (e.g., the lens surface on the display unit 30 side of the lens Lf shown in FIG. 9A) of the photographed image Im, which is the focal plane, or the surface on which the photographed image Im is arranged.

[0080] In the optical unit 42 in this embodiment, the lens surface where the chief ray is most separated is the lens surface closest to the display unit 30, and on that lens surface (for example, the lens surface on the display unit 30 side of the lens Lf in FIG. 9A described later), the chief ray of the on-axis light JI (hereinafter referred to as the chief ray of the central angle of view) and the chief ray of the off-axis light JE (hereinafter referred to as the chief ray of the maximum angle of view) that has the maximum angle of view at the outermost part of the area where the captured image Im can be displayed are separated from each other. The optical unit 42 is configured so that when the chief ray of the maximum angle of view passes through the lens surface closest to the display unit 30 of the optical unit 42, the chief ray passes through the lens surface at a position longer than half the length from the optical axis (for example, the optical axis CL) to the effective diameter of the lens through which the chief ray passes and away from the optical axis in the effective diameter of the lens. For example, the chief ray of the maximum angle of view passes outside a concentric region having a diameter equal to half the length of the effective diameter of the lens in the effective diameter of the lens. This is because the respective chief rays of the on-axis light JI and the off-axis light JE are separated on the lens surface closest to the display unit 30, making it possible to define a spherical or aspherical surface that provides optimal refraction for each.

[0081] As a result, it was found that even if the eyebox area is enlarged, the coma aberration, lateral chromatic aberration, and distortion of off-axis light can be corrected without worsening the aberration of on-axis light by configuring the optical unit 42 so as to satisfy the fourth design condition, and even if the eyebox area is enlarged, the coma aberration, lateral chromatic aberration, and distortion of off-axis light can be corrected without worsening the aberration of on-axis light, but more detailed aberration correction can be achieved by making the chief ray of the maximum angle of view pass through an area outside the concentric area having a diameter that is half the length of the effective diameter of the lens in the optical system.

[0082] Therefore, the seventh design condition is: When the chief ray of the maximum angle of view passes through the lens surface of the optical unit 42 closest to the display unit 30, it passes through an area (e.g., an area farther from the optical axis) outside the concentric area having a diameter equal to half the length of the effective diameter of the lens in the effective diameter of the lens. In other words, it is preferable to configure the optical unit 42 so that the chief ray of the maximum angle of view caused by the light of the captured image (display image) Im passes through a position with a diameter larger than 1 / 2 the effective diameter of the lens into which it is incident (e.g., lens Lf shown in FIG. 9A). That is, the seventh design condition is: The distance of the captured image Im displayed by the display unit 30 (for example, the distance or size indicating the diameter of the inscribed circle, the diameter of the circumscribed circle, the length of the sides and the diagonal lines, etc. of the image display area) is D, and the effective diameter of the lens of the optical unit 42 closest to the display unit 30 is φ LF , the distance between the display unit 30 and the lens of the optical unit 42 closest to the display unit 30 is d3, and the distance between the display unit 30 and the entrance pupil Inp is P IN If the condition value Q is 1 / 2 <Q<1 Q = [D·{1-(d3 / P IN )}] / φ LF The optical unit 42 is configured so as to satisfy the seventh conditional expression:

[0083] FIG. 9A shows a schematic configuration of the optical unit 42. FIG. 9B shows an enlarged view of the periphery of the pupil. In FIG. 9A, the entrance pupil Inp and the exit pupil Exp are close to each other, so the illustration of the exit pupil Exp is omitted. In FIG. 9B, the positional relationship between the entrance pupil Inp and the exit pupil Exp is exaggerated. The entrance pupil Inp is a position where the chief ray intersects with the light from the captured image Im when the chief ray of each angle of view is caused to travel in a straight line. For example, as shown in FIG. 9B, the position where the light ray (shown by a dotted line in FIG. 9B) assuming that the chief ray of the maximum angle of view incident on the optical unit 42 travels in a straight line and the light ray (shown by a dashed line in FIG. 9B) assuming that the chief ray of the central angle of view travels in a straight line intersects with each other is the position of the entrance pupil Inp. On the other hand, the position of the exit pupil Exp is the position where the chief rays intersect when they are reversed at each angle of view to reach the image plane, i.e., the position where the refracted chief rays (the rays indicated by the two-dot chain lines in Figure 9B) intersect.

[0084] As shown in FIG. 9A, the chief ray at the maximum angle of view is (D / 2) / P IN The light is incident on the optical unit 42 at an inclination indicated by . In this case, the height h from the optical axis to the lens surface of the lens Lf of the optical unit 42 that is closest to the display unit 30 is expressed by the following equation. h=(D / 2)-{(D / 2) / P IN}·d3 =(D / 2)·{1-(d3 / P IN )} Therefore, the condition value Q can be expressed by the following formula, and the effective diameter φ of the lens of the optical unit 42 closest to the display unit 30 is LF and a height h indicating the position where the principal ray of the maximum angle of view passes through the lens. Q = h (2 / φ LF )

[0085] In the example shown in FIG. 9A, the lens surface of the lens Lf on the display unit 30 side of the optical unit 42 is an example of a first refractive surface in which the first surface into which the light of the captured image Im of the present disclosure is incident is a convex surface facing the light incident side. In addition, the lens surface of the lens Le on the observer OP side of the optical unit 42 is an example of a second refractive surface in which the second surface from which the light is emitted is a convex surface facing the light exit side of the present disclosure. The lens surface of the lens Lf on the display unit 30 side is an example of the first surface from which the light is incident to the optical unit 42, and the lens surface of the lens Le on the observer OP side is an example of the last surface from which the light is emitted from the optical unit 42. Furthermore, the lens Lf is an example of the first lens of the present disclosure, the lens Le is an example of the second lens of the present disclosure, and the optical unit 42 including the lens Lf and the lens Le is an example of a lens group of the present disclosure.

[0086] Next, the above design conditions will be verified using a specific example of a lens of the optical unit 42.

[0087] First, it is considered difficult to form an optical unit 42 capable of correcting off-axis aberrations while forming a large eyebox area IB using a single lens. The optical unit 42 using a single lens, in which it has been difficult to correct off-axis aberrations, will be described.

[0088] <Lens example 1> 10 shows an example of the configuration of optical unit 42 having one lens in one group and an example of the optical path as lens example 1. Since optical unit 42R and optical unit 42L have the same configuration, individual description will be omitted below. As shown in Fig. 10, the optical unit 42 is formed of a single lens having optical surfaces with surface numbers P1 and P2 in order from the captured image Im. The optical surface becomes a refractive surface when the refractive index of the medium on one side of the optical surface differs from the refractive index of the medium on the other side. Note that the example shown in Fig. 10 shows a case where the optical unit 42 is disposed at a distance d0 of 69.7 mm from the captured image Im to the end of the lens surface closest to the display unit 30.

[0089] Table 1 below shows the values ​​of the specifications of the optical unit 42 of the first lens example. In Table 1, surface number m corresponds to the surface number of the optical surface shown in Fig. 10. Furthermore, radius of curvature r indicates the radius of curvature of each optical surface, surface interval d indicates the distance on the optical axis from each optical surface to the next optical surface, refractive index nd indicates the refractive index for the d line, and dispersion vd indicates the Abbe number. In the specifications shown in Table 1, "mm" is used as the unit of radius of curvature r and surface interval d, but since the optical unit 42 can obtain the same optical performance even when proportionally enlarged or reduced, the unit is not limited to "mm" and other units can be used.

[0090] [Table 1]

[0091] Table 1 shows an example of a spherical optical surface with the optical axis CL as an axis, and the optical surface is not limited to a spherical shape, and may be aspherical. The same applies to other lens examples described below. In addition, the effective diameter of the lens in Lens Example 1 is 24.83, and it is assumed that the distance of the captured image Im (the distance or size of the image display area) is 31.66.

[0092] The optical unit 42 functions as an objective lens, which is an afocal optical system, and emits light from the captured image Im as parallel light. That is, the optical unit 42 has a focal length f, and is set so that the captured image Im of the object captured by the display unit 30 is located at the focal point on the light incident side, and the display unit 30 is attached to the optical unit 42. In this way, the optical unit (optical system having the above-mentioned lens) 42 has a focal point on the light incident side at the position where the captured image (display image) Im of the object is set, and emits light from the focal plane (in this case, the captured image Im, or the surface on which the captured image Im is located) as parallel light.

[0093] 10, the optical unit 42 is set so that a photographed image Im (displayed image) of the object by the display unit 30 is located at the focal position of the focal length f on the display unit 30 side, forming an afocal optical system, and the light emitted from the optical unit 42 toward the observer OP becomes parallel light. The parallel light emitted from the optical unit 42 reaches the eye of the observer OP and forms an image on the retina of the observer OP, and the photographed image Im is perceived by the observer OP.

[0094] 10, the value (=d1 / d2) of the fourth conditional expression is 0.19, and the value (=Q) of the seventh conditional expression is 0.323. The optical unit 42 of the lens example 1 does not satisfy the fourth design condition, and although the eyebox area formed by the optical unit 42 can be enlarged, it is difficult to correct aberrations due to coma aberration, lateral chromatic aberration, and distortion of off-axial light. In other words, the aberration of on-axial light is worsened by correcting the aberration of off-axial light.

[0095] Furthermore, the optical unit 42 of Lens Example 1 does not satisfy the seventh design condition, and the separation of the chief ray of the central angle of view and the chief ray of the maximum angle of view is insufficient on the lens surface of the optical unit 42 closest to the display unit 30. For this reason, it is difficult to define a spherical or aspherical surface that provides appropriate refraction for each of the central angle of view and the maximum angle of view. Therefore, although it is possible to enlarge the eyebox area by configuring the optical unit 42 from a single lens, it is considered that image quality degradation occurs in the image viewed by the observer OP because aberrations that are difficult to correct remain.

[0096] <Lens example 2> Next, an optical unit 42 will be described which attempts to correct aberrations while forming a large eyebox area IB using a single lens. FIG. 11 shows an example of the configuration of an optical unit 42 having one lens in one group, the specifications of which are different from those of the lens example 1, and an example of an optical path. The optical unit 42 shown in FIG. 11 is disposed such that the distance d0 from the captured image Im to the end of the lens surface closest to the display unit 30 is 73.76 mm.

[0097] Table 2 below shows the values ​​of the specifications of the optical unit 42 of the second lens example. In Table 2, the surface number m corresponds to the surface number of the optical surface shown in FIG. 3. The radius of curvature r indicates the radius of curvature of each optical surface, the surface interval d indicates the distance on the optical axis from each optical surface to the next optical surface, the refractive index nd indicates the refractive index for the d line, and the dispersion νd indicates the Abbe number. In the specifications shown in Table 2, the unit of the radius of curvature r and the surface interval d is "mm", but since the optical unit 42 can obtain the same optical performance even if it is proportionally enlarged or reduced, the unit is not limited to "mm" and other units can be used. In addition, the effective diameter of the lens in Lens Example 2 is 29.02, and it is assumed that the distance of the captured image Im (the distance or size of the image display area) is 30.99.

[0098] [Table 2]

[0099] The optical unit 42 of the lens example 2 has a value (=d1 / d2) according to the fourth conditional expression of 0.455, and a value (=Q) according to the seventh conditional expression of 0.553. The optical unit 42 of the lens example 2 satisfies the seventh design condition. Therefore, it is possible to define a spherical or aspherical surface that provides appropriate refraction for each of the central angle of view and the maximum angle of view on the lens surface closest to the display unit 30. However, the optical unit 42 of the lens example 2 does not satisfy the fourth design condition. Therefore, although it is possible to enlarge the eyebox area formed by the optical unit 42, it is difficult to correct aberrations due to coma aberration, chromatic aberration of magnification, and distortion of off-axis light, and correcting the aberration of off-axis light worsens the aberration of on-axis light.

[0100] In this way, when the optical unit 42 is configured with a single lens, it is possible to enlarge the eyebox region formed by the optical unit 42, but it may be difficult to correct aberrations due to off-axis coma aberration, lateral chromatic aberration, and distortion. However, by satisfying the seventh design condition, it is considered that aberration correction that can be expected to improve image quality is possible. That is, in the lens example 2, it is possible to enlarge the eyebox region, and although it creates a situation in which it is difficult to correct various aberrations, it is possible to define a spherical or aspherical surface that provides appropriate refraction for each of the central angle of view and the maximum angle of view, and therefore it is expected that the image viewed by the observer OP will have an improved image quality compared to a lens that does not satisfy the seventh design condition.

[0101] <Lens example 3> FIG. 12 shows, as lens example 3, an example of the configuration of an optical unit 42 made of one group of two lenses and an example of an optical path. The optical unit 42 shown in Fig. 12 is formed of one group of two lenses having optical surfaces with surface numbers P1, P2, and P3 in order from the captured image Im. Note that the example shown in Fig. 12 shows a case where the optical unit 42 is disposed at a distance d0 of 69.7 mm from the captured image Im.

[0102] Table 3 below shows values ​​of the specifications of the optical unit 42 according to Lens Example 3. Note that the effective diameter of the lens in Lens Example 3 is 31.20, and it is assumed that the distance of the captured image Im (the distance or size of the image display area) is 31.19.

[0103] [Table 3]

[0104] For the optical unit 42 of Lens Example 3, the value (=d1 / d2) according to the fourth conditional expression is 0.53, and the value (=Q) according to the seventh conditional expression is 0.643. The optical unit 42 of Lens Example 3 satisfies the fourth design condition, and it is possible to increase the size of the eyebox area formed by the optical unit 42, and it is possible to correct aberrations due to off-axial coma aberration, lateral chromatic aberration, and distortion.

[0105] Furthermore, the optical unit 42 of Lens Example 3 also satisfies the seventh design condition, and the chief rays of the central angle of view and the maximum angle of view can be separated at the lens surface of the optical unit 42 that is closest to the display unit 30. This makes it possible to define a spherical or aspherical surface that provides appropriate refraction for each of the central angle of view and the maximum angle of view. Therefore, in Lens Example 3, the eyebox area can be enlarged and various aberrations can be corrected, so that improvement in the image quality viewed by the observer OP can be expected.

[0106] When optical unit 42 is formed with a lens configuration of two lenses in one group, the second surface is filled with glass material, which is not preferable in terms of cost and weight, and a configuration of two or more groups is preferable.

[0107] <Lens example 4> FIG. 13 shows, as lens example 4, an example of the configuration of an optical unit 42 made of three lenses in two groups and an example of the optical path. The optical unit 42 shown in Fig. 13 is formed of three lenses in two groups, each having optical surfaces with surface numbers P1, P2, P3, P4, and P5, in that order from the captured image Im. Note that the example shown in Fig. 13 shows a case where the optical unit 42 is disposed at a distance d0 of 62.8 mm from the captured image Im.

[0108] Table 4 below shows values ​​of the specifications of the optical unit 42 according to Lens Example 4. Note that the effective diameter of the lens in Lens Example 4 is 33.45, and it is assumed that the distance of the captured image Im (the distance or size of the image display area) is 31.26.

[0109] [Table 4]

[0110] The optical unit 42 according to the lens example 4 has a value (=d1 / d2) according to the fourth conditional expression of 0.60, and a value (=Q) according to the seventh conditional expression of 0.737. The optical unit 42 according to the lens example 4 satisfies the fourth design condition, and can enlarge the eyebox area formed by the optical unit 42, and can correct aberrations due to coma aberration, lateral chromatic aberration, and distortion of off-axis light. The optical unit 42 according to the lens example 4 also satisfies the seventh design condition, and can separate the chief rays of the central angle of view and the maximum angle of view on the lens surface of the optical unit 42 closest to the display unit 30. For this reason, it was possible to define a spherical surface or an aspheric surface that provides appropriate refraction for each of the central angle of view and the maximum angle of view. Therefore, in Lens Example 4, the eyebox area can be enlarged and various aberrations can be corrected, so that improvement in the quality of the image viewed by the observer OP can be expected.

[0111] <Lens example 5> FIG. 14 shows, as lens example 5, an example of the configuration of an optical unit 42 made of three lenses in three groups and an example of the optical path. The optical unit 42 shown in Fig. 14 is formed of three lenses in three groups, each having optical surfaces with surface numbers P1, P2, P3, P4, P5, and P6, in that order from the captured image Im. Note that the example shown in Fig. 14 shows a case where the optical unit 42 is disposed at a distance d0 of 43.8 mm from the captured image Im.

[0112] Table 5 below shows the values ​​of the specifications of the optical unit 42 according to Lens Example 5. Note that the effective diameter of the lens in Lens Example 5 is 32.16, and it is assumed that the distance of the captured image Im (the distance or size of the image display area) is 31.59.

[0113] [Table 5]

[0114] The optical unit 42 according to the lens example 5 has a value (=d1 / d2) according to the fourth conditional expression of 0.69, which satisfies the fourth design condition. In addition, the value (=Q) according to the seventh conditional expression of 0.816 also satisfies the seventh design condition. Therefore, the optical unit 42 according to the lens example 5 can enlarge the eyebox area and can correct aberrations due to coma aberration, lateral chromatic aberration, and distortion of off-axis light. In addition, the lens surface closest to the display unit 30 can separate the chief rays of the central angle of view and the maximum angle of view, and it is possible to define a spherical or aspherical surface that provides appropriate refraction independently for each of the central angle of view and the maximum angle of view. Therefore, in Lens Example 5, the eyebox area can be enlarged and various aberrations can be corrected, so that improvement in the quality of the image viewed by the observer OP can be expected.

[0115] <Lens Example 6> FIG. 15 shows, as lens example 6, an example of the configuration of an optical unit 42 made of four lenses in three groups and an example of the optical path. The optical unit 42 shown in Fig. 15 is formed of three groups of four lenses having optical surfaces with surface numbers P1, P2, P3, P4, P5, P6, and P7 in order from the captured image Im. Note that the example shown in Fig. 15 shows a case where the optical unit 42 is disposed at a distance d0 of 19.5 mm from the captured image Im.

[0116] Table 6 below shows the values ​​of the specifications of the optical unit 42 according to Lens Example 6. Note that the effective diameter of the lens in Lens Example 6 is 28.38, and it is assumed that the distance of the captured image Im (the distance or size of the image display area) is 31.80.

[0117] [Table 6]

[0118] The optical unit 42 according to the lens example 6 has a value (=d1 / d2) according to the fourth conditional expression of 0.85, which satisfies the fourth design condition. In addition, the value (=Q) according to the seventh conditional expression of 0.80, which also satisfies the seventh design condition. Therefore, the optical unit 42 according to the lens example 6 can enlarge the eyebox area and can correct aberrations due to coma aberration, lateral chromatic aberration, and distortion of off-axis light. In addition, the lens surface closest to the display unit 30 can separate the chief rays of the central angle of view and the maximum angle of view, and it is possible to define a spherical or aspherical surface that provides appropriate refraction independently for each of the central angle of view and the maximum angle of view. Therefore, in Lens Example 6, the eyebox area can be enlarged and various aberrations can be corrected, so that improvement in the quality of the image viewed by the observer OP can be expected.

[0119] <Lens Example 7> FIG. 16 shows an example of the configuration of an optical unit 42 including three lenses in two groups, which has different specifications from those of the fourth lens example, and an example of an optical path. The optical unit 42 shown in Fig. 16 is formed of three lenses in two groups, each having optical surfaces with surface numbers P1, P2, P3, P4, and P5, in that order from the captured image Im. Note that the example shown in Fig. 16 shows a case where the optical unit 42 is disposed at a distance d0 of 10.0 mm from the captured image Im.

[0120] Table 7 below shows the values ​​of the specifications of the optical unit 42 according to Lens Example 7. Note that the effective diameter of the lens in Lens Example 7 is 29.46, and it is assumed that the distance of the captured image Im (the distance or size of the image display area) is 30.47.

[0121] [Table 7]

[0122] The optical unit 42 of the lens example 7 has a value (=d1 / d2) according to the fourth conditional expression of 0.97, which satisfies the fourth design condition. In addition, the value (=Q) according to the seventh conditional expression of 0.911, which satisfies the seventh design condition. Therefore, the optical unit 42 of the lens example 7 can enlarge the eyebox area and can correct aberrations due to coma aberration, lateral chromatic aberration, and distortion of off-axis light. In addition, the lens surface closest to the display unit 30 can separate the chief rays of the central angle of view and the maximum angle of view, and it is possible to define a spherical or aspherical surface that provides appropriate refraction independently for each of the central angle of view and the maximum angle of view. Therefore, in Lens Example 7, the eyebox area can be enlarged and various aberrations can be corrected, so that improvement in the quality of the image viewed by the observer OP can be expected.

[0123] <Lens Example 8> FIG. 17 shows an example of the configuration of an optical unit 42 including three lenses in three groups, which has different specifications from those of the fifth lens example, and an example of an optical path. The optical unit 42 shown in Fig. 17 is formed of three lenses in three groups, each having optical surfaces with surface numbers P1, P2, P3, P4, P5, and P6, in that order from the captured image Im. Note that the example shown in Fig. 17 shows a case where the optical unit 42 is disposed at a distance d0 of 8.3 mm from the captured image Im.

[0124] Table 8 below shows the values ​​of the specifications of the optical unit 42 according to Lens Example 8. Note that the effective diameter of the lens in Lens Example 8 is 29.27, and it is assumed that the distance of the captured image Im (the distance or size of the image display area) is 29.41.

[0125] [Table 8]

[0126] The optical unit 42 according to the lens example 8 has a value (=d1 / d2) according to the fourth conditional expression of 0.99, which satisfies the fourth design condition. In addition, the value (=Q) according to the seventh conditional expression of 0.919, which also satisfies the seventh design condition. Therefore, the optical unit 42 according to the lens example 8 can enlarge the eyebox area and can correct aberrations due to coma aberration, lateral chromatic aberration, and distortion of off-axis light. In addition, the lens surface closest to the display unit 30 can separate the chief rays of the central angle of view and the maximum angle of view, and it is possible to define a spherical or aspherical surface that provides appropriate refraction independently for each of the central angle of view and the maximum angle of view. Therefore, in Lens Example 8, the eyebox area can be enlarged and various aberrations can be corrected, so that improvement in the quality of the image viewed by the observer OP can be expected.

[0127] <Lens Example 9> FIG. 18 shows an example of the configuration of an optical unit 42 including three lenses in three groups, which has specifications different from those of lens example 5 and lens example 8, and an example of an optical path. The optical unit 42 shown in Fig. 18 is formed of three lenses in three groups, each having optical surfaces with surface numbers P1, P2, P3, P4, P5, and P6, in that order from the captured image Im. Note that the example shown in Fig. 18 shows a case where the optical unit 42 is disposed at a distance d0 of 63.8 mm from the captured image Im.

[0128] Table 9 below shows the values ​​of the specifications of the optical unit 42 according to Lens Example 9. Note that the effective diameter of the lens in Lens Example 9 is 27.38, and it is assumed that the distance of the captured image Im (the distance or size of the image display area) is 31.94.

[0129] [Table 9]

[0130] The optical unit 42 of the lens example 9 has a value (=d1 / d2) according to the fourth conditional expression of 0.48, and a value (=Q) according to the seventh conditional expression of 0.572. The optical unit 42 of the lens example 9 satisfies the seventh design condition. Therefore, it is possible to define a spherical or aspherical surface that provides appropriate refraction for each of the central angle of view and the maximum angle of view on the lens surface closest to the display unit 30. However, the optical unit 42 of the lens example 9 does not satisfy the fourth design condition. Therefore, although it is possible to enlarge the eyebox area formed by the optical unit 42, it is difficult to correct aberrations due to coma aberration, chromatic aberration of magnification, and distortion of off-axis light, and correcting the aberration of off-axis light worsens the aberration of on-axis light. Therefore, in Lens Example 9, although it is possible to increase the size of the eyebox area and make it difficult to correct various aberrations, it is possible to define a spherical or aspherical surface that provides appropriate refraction for each of the central angle of view and the maximum angle of view, and therefore it is expected that the image viewed by the observer OP will have an improved quality, as compared to a lens that does not satisfy the seventh design condition.

[0131] As described above, by configuring the optical unit 42 so as to satisfy the above design conditions, the optical unit 42 can enlarge the eyebox area and can correct aberrations due to off-axial coma aberration, lateral chromatic aberration, and distortion. In addition, the chief ray of the central angle of view and the chief ray of the maximum angle of view can be separated on the lens surface closest to the display unit 30, and it is possible to define a spherical or aspherical surface that provides appropriate refraction independently for each of the central angle of view and the maximum angle of view.

[0132] In this embodiment, the optical unit 42 is configured so that the exit pupil Exp is located on the light exit side. This forms a wide eyebox area IB on the light exit side of the optical unit 42, i.e., on the viewing side of the observer OP, improving the degree of freedom in setting the head position of the observer OP.

[0133] FIG. 19 shows an example of an exit pupil Exp in the image display device 40 according to this embodiment. As shown in FIG. 19, the image display device 40 has an exit pupil Exp formed as an exit pupil ExpR for the right eye and an exit pupil ExpL for the left eye.

[0134] In this embodiment, the exit pupil Exp is formed to be located on the light exit side of the optical unit 42. This makes it possible to form the exit pupil of the optical unit 42 to a size corresponding to the lens diameter of the optical unit 42, and the maximum value of the diameter of the exit pupil ExpR for the right eye and the exit pupil ExpL for the left eye can be expanded to a size corresponding to the lens diameter of the optical unit 42. If each eye of the observer OP is positioned within each of the exit pupils ExpR for the right eye and the exit pupil ExpL for the left eye, the observer OP can view each of the captured image ImR for the right eye and the captured image ImL for the left eye of the observer OP. Therefore, the ophthalmologic system 10 of this embodiment does not require a mechanism for adjusting the interpupillary distance PD, which is provided in a conventional binocular microscope.

[0135] Incidentally, the size, i.e., diameter, of the right-eye exit pupil ExpR and the left-eye exit pupil ExpL is limited by the lens diameter of the optical unit 42. On the other hand, there are cases where it is required to increase the size of the exit pupil Exp to expand the range visible to the observer OP. In this case, the lens diameter of the optical unit 42 may be made larger than the interpupillary distance PD so that parts of the optical units 42 overlap.

[0136] That is, when the image display device 40 is configured with an optical unit 42R for the right eye and an optical unit 42L for the left eye, it is preferable that the diameter of each of the optical units 42R for the right eye and the optical unit 42L for the left eye is formed to be less than the distance corresponding to the interpupillary distance PD of the observer OP observing the captured image (displayed image) Im. When at least one of the right-eye optical units 42R and the left-eye optical unit 42L is configured in the image display device 40 beyond the diameter of the distance corresponding to the interpupillary distance PD of the observer OP, an overlapping portion is generated where the right-eye optical units 42R and the left-eye optical unit 42L overlap each other. In this case, a part of at least one of the right-eye optical units 42R and the left-eye optical unit 42L may be removed (for example, a so-called D cut) from the overlapping portion so that the right-eye optical units 42R and the left-eye optical unit 42L do not overlap each other.

[0137] FIG. 20 shows an example of the configuration of the optical unit 42 in which the lens diameter is made larger than the interpupillary distance PD. If the lens diameter of the optical unit 42 is made larger than the interpupillary width PD, the optical unit 42R for the right eye and the optical unit 42L for the left eye will interfere with each other, so at least one of the optical units 42, the optical unit 42R for the right eye and the optical unit 42L for the left eye, may be formed by removing the interfering portion. The example shown in FIG. 20 shows a case where the optical unit 42 is formed by removing a part of the optical unit 42 evenly from the optical unit 42R for the right eye and the optical unit 42L for the left eye. In this way, a larger exit pupil Exp can be formed as the distance between the optical axis of the optical unit 42R for the right eye and the optical axis of the optical unit 42L for the left eye, while maintaining the preset interpupillary width PD, compared to the case where the optical unit 42 is formed with a diameter corresponding to the interpupillary width PD.

[0138] By the way, by forming a wide eye box area IB outside the exit side of the optical unit 42, the degree of freedom in setting the head position of the observer OP is improved, but there is a risk that disturbance light may enter the eyes of the observer OP. In order to solve this problem, a suppression member for suppressing disturbance light may be provided in the optical path leading to the eyes of the observer OP as disturbance light to suppress the intrusion of disturbance light.

[0139] FIG. 21 shows an example of a suppression member that suppresses disturbance light from entering the eyes of the observer OP. As shown in Fig. 21, the image display device 40 according to this embodiment includes a housing case 41 that houses an optical unit 42R for the right eye and an optical unit 42L for the left eye. The housing case 41 covers at least the optical unit 42R for the right eye and the optical unit 42L for the left eye, and has a function of blocking disturbance light to the optical unit 42R for the right eye and the optical unit 42L for the left eye. The housing case 41 also has an opening 41H on the light exit side of each of the optical unit 42R for the right eye and the optical unit 42L for the left eye. The opening 41H is formed so as not to block the optical path leading to the exit pupil Exp.

[0140] A light shielding plate 43A is attached to the housing case 41 as a suppression member on the light emission side of the opening 41H, that is, on the observer OP side. The light shielding plate 43A only needs to have a function of suppressing disturbance light, and an optical member such as a plate that blocks disturbance light, or an optical member that attenuates light transmission, such as an ND filter, can be used. Note that, in the example shown in FIG. 21, an example is shown in which the light shielding plate 43A is attached in three directions, namely, above and to the left and right, but it may be provided in a portion that suppresses light in at least one main direction as disturbance light, or may be provided so as to cover the top, bottom, left and right. The light shielding plate 43A is an example of a light suppression section of the present disclosure.

[0141] FIG. 22 shows another example of a suppression member for suppressing disturbance light from entering the eyes of the observer OP. In the example shown in FIG. 22, a suppression member 43BR for the right eye and a suppression member 43BL for the left eye are attached to the housing case 41. Each of the suppression members 43BR and 43BL is formed of an elastic member such as rubber that suppresses discomfort when the head of the observer OP contacts the suppression members 43BR and 43BL. This allows the observer OP to suppress disturbance light by contacting the head of the suppression members 43BR and 43BL. Note that the example shown in FIG. 22 shows an example in which an opening 41Ha having a diameter smaller than the opening 41H shown in FIG. 21 is provided in each of the suppression members 43BR and 43BL. The size of the opening 41Ha is a predetermined shape assuming an eye relief when the observer OP contacts the head of the suppression members 43BR and 43BL. Note that the size of the opening 41Ha is not limited to the size shown in FIG. 22. The suppression members 43BR and 43BL are an example of a light suppression unit of the present disclosure.

[0142] Modifications In this embodiment, a system (ophthalmic system) applied to an ophthalmic device has been described as an example of an image display device according to the present disclosure, but the image display device according to the present disclosure can also be applied to other ophthalmic devices that enable stereoscopic vision. For example, the present disclosure can also be applied to other ophthalmic devices that present an aerial image by making the eyebox area IB larger, that is, provide a relayed exit pupil. An image display device with the larger eyebox area IB will be described as a modified example.

[0143] FIG. 23 shows an example of the configuration of a modified image display device 40A in which the eye box area IB is made larger. 23, in the modified example, a relay unit 44 that relays the pupil is attached to the above-mentioned image display device 40. In the image display device 40A of the modified example, the subject's eye and the periphery of the subject's eye are photographed by the photographing unit 20, and the photographed image is presented by the above-mentioned image display device 40, and provided to the observer OP by the relay unit 44.

[0144] The relay unit 44 includes a housing 46 and an optical member 48. The above-mentioned image display device 40 including the optical unit 42 is attached to the housing 46, and light emitted from the optical unit 42 is incident inside the housing 46. Furthermore, inside the housing 46, on the light emission side of the optical unit 42, the optical member 48 is attached so as to reflect the light in a direction intersecting the emission optical axis of the optical unit 42 (direction toward the observer OP). The relay unit 44 reflects the light emitted from the optical unit 42 in a direction intersecting the emission optical axis of the optical unit 42, and forms a position on the reflection side that is conjugate with the exit pupil Exp of the optical unit 42. That is, the relay unit 44 relays the exit pupil by reforming the exit pupil Exp of the optical unit 42 on the reflection side, which is the direction toward the observer OP.

[0145] The housing 46 of the relay unit 44 to which the image display device 40 described above is attached is attached to a base (not shown), and is formed independently from the imaging unit 20 and formed in a non-contact state with respect to the observer OP. By forming the image display device 40A of the modified example in a non-contact state with respect to the observer OP, the discomfort felt by the observer OP due to the observer OP coming into contact with the image display device 40A of the modified example is suppressed.

[0146] An example of the optical member 48 shown in the modified example can be an optical imaging element that forms an image at the same magnification by multiple reflections by multiple reflecting surfaces. For example, the optical imaging element includes multiple reflecting members in which multiple reflecting surfaces are stacked, and light incident from one stacking end surface is reflected by the reflecting surface and emitted from the other stacking end surface. The multiple reflecting members are arranged such that the reflecting surface of one reflecting member and the reflecting surface of another reflecting member are oriented in a crossing direction, and the light emitted from the stacking end surface of one reflecting member is incident on the stacking end surface of the other reflecting member.

[0147] That is, the incident light incident on the optical imaging element, which is an example of the optical member 48, is reflected by the first reflecting surface, and the reflected light is reflected by the second reflecting surface and is emitted from the optical imaging element. On the other hand, in the optical imaging element, the first reflecting surface and the second reflecting surface are arranged in a direction in which the reflecting surfaces cross each other (orthogonal). In this way, when the first reflecting surface and the second reflecting surface are arranged orthogonal to each other in a planar view, the incident light to the optical imaging element and the emitted light from the optical imaging element become parallel in a planar view of the optical imaging element. Therefore, each of the multiple light points that are object points on the entrance side of the optical imaging element is focused on the exit side of the optical imaging element and imaged as an image point. Therefore, the relay unit 44 re-forms the exit pupil Exp at a position that is in a conjugate relationship with the exit pupil Exp of the optical unit 42.

[0148] In addition, the optical imaging element, which is an example of the optical member 48, can be treated as a retroreflection element, more specifically, a retrotransmission element. Retroreflection reflects light in the opposite direction to the direction of the light incident on the element at multiple orthogonal reflective surfaces. On the other hand, the optical imaging element has the property of transmitting the incident light to the surface opposite to the incident surface, and at that time, changing the direction and emitting the light, and the light beam is folded back symmetrically with respect to a plane perpendicular to the normal line of the optical imaging element. This corresponds to the optical imaging element acting retroreflectively when folding back the space, without changing the traveling direction of the light beam in the vertical direction of the optical imaging element, and therefore can be considered as a retrotransmission element.

[0149] Another example of an optical imaging element is a light control panel in which a plurality of intersecting reflecting surfaces are used as unit optical systems, and the unit optical systems are arranged in a plane direction intersecting the plurality of reflecting surfaces. The control panel is formed by arranging a plurality of unit optical systems, for example, dihedral corner reflectors, each of which has two mirror surfaces that are substantially perpendicular to a predetermined plane and are substantially orthogonal to each other.

[0150] In addition, in the present embodiment, a system applied to an ophthalmic device has been described as an example of an image display device according to the present disclosure, but the image display device according to the present disclosure is not limited to an ophthalmic system applied to an ophthalmic device. That is, the image display device according to the present disclosure is applicable to any device that displays an image, and the image display system according to the present disclosure is applicable to any system equipped with a device that displays an image. Next, application examples of an image display device to which the present disclosure can be applied and an image display system equipped with an image display device will be illustrated.

[0151] Application Examples An example of application is application to a display device of an observation system for observing a distant object using optical equipment such as binoculars and a periscope. By applying the image display device according to the present disclosure to this observation system for observing a distant object, the observer OP can observe the distant object without contacting the image display device 40, and the discomfort of the observer OP caused by contact is suppressed. In addition, since the apparent size of the image viewed by the optical unit 42 does not change, the head of the observer OP can move within the eye box area. Therefore, there is a greater tolerance for the posture of the observer OP compared to a posture in which the observer OP's head touches an optical equipment such as binoculars and a periscope. In the present embodiment, the system applied to an ophthalmic device has been described as an example of an image display device according to the present disclosure, but the image display device according to the present disclosure can also be applied to a case where each of a plurality of observers can visually observe an object. For example, the system may include a plurality of image display devices according to the present disclosure, and the same image may be displayed on each of the plurality of image display devices, or an image that has been subjected to image processing may be displayed on some of the image display devices.

[0152] Although the embodiments of the present disclosure have been described, the technical scope of the present disclosure is not limited to the scope described in the above embodiments. Various modifications or improvements can be made to the above embodiments without departing from the gist of the present disclosure, and the forms in which such modifications or improvements are made are also included in the technical scope of the present disclosure. In addition, all documents, patent applications, and technical standards described in this specification are incorporated by reference in this specification to the same extent as if each document, patent application, and technical standard was specifically and individually stated to be incorporated by reference. [Explanation of symbols]

[0153] 10 Ophthalmology Systems 20. Photography Department 22 Microscope 24 Camera 26 Camera Controller 30 Display section 40 Image display device 42 Optical unit IB Eye Box Area Im Photo OB Object OP Observer

Claims

1. an optical system having a focal point on a light incident side at a position where a display image of an object is set, and emitting light from the focal plane as parallel light; a housing portion that houses the optical system, a visible region in which the display image can be viewed is derived based on an effective diameter of a lens included in the optical system and an angle between a chief ray of a maximum angle of view and an optical axis of the optical system; If the angle between the chief ray of the maximum angle of view in the optical system and the optical axis of the optical system is ω, 15 degrees≦ω≦50 degrees The visible area is formed so as to satisfy the conditional expression represented by When the visible area in which the display image can be viewed is IB, 185000≧IB≧7570mm ３ The conditional expression shown in The optical system has a first lens and a second lens, a first surface of the first lens, which is an initial surface through which light enters the optical system, is formed by a first refractive surface having a convex surface facing the light incident side, and a second surface of the second lens, which is a final surface through which the light exits, is formed by a second refractive surface having a convex surface facing the light exit side, When the distance from the end of the first refractive surface to the end of the second refractive surface is d1 and the distance from the position of the display image to the end of the second refractive surface is d2, 1>d1 / d2>0.5 and corrects at least one off-axis aberration of off-axis light, including coma aberration, lateral chromatic aberration, and distortion. Optical unit.

2. The optical system forms a pupil at a position on the exit side of the light. The optical unit according to claim 1 .

3. The visible area is derived based on the effective diameter of the lens included in the optical system and the angle between the chief ray of the maximum angle of view and the optical axis of the optical system. The optical unit according to claim 1 or 2.

4. If the angle between the chief ray of the maximum angle of view in the optical system and the optical axis of the optical system is ω, ω≦50 degrees The visible area is formed so as to satisfy the conditional expression The optical unit according to claim 3 .

5. In the optical system, when an effective diameter of the first lens onto which light of the display image is incident is φ, a distance of the display image is D, a distance from a position of the display image to the first lens is d3, and a distance from the position of the display image to a position of an entrance pupil of the optical system is Pin, 1 / 2<D・(1-d3 / Pin) / φ<1 It is constructed to satisfy the conditional expression shown in The optical unit according to any one of claims 1 to 4.

6. When the focal length of the optical system is f, the angle between the chief ray of the maximum angle of view and the optical axis of the optical system is ω, and the distance of the display image is D, f≦(D / 2) / sinω 6. The optical unit according to claim 1, wherein the focal length is set to be 25 mm or more and 100 mm or less so as to satisfy the conditional expression:

7. The optical system includes one doublet lens. The optical unit according to any one of claims 1 to 6.

8. A display device for displaying a display image of the object is provided in a removable mounting portion. The optical unit according to any one of claims 1 to 7.

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