Display device, control method thereof, and recording medium

Abstract

The present disclosure relates to a display apparatus, a control method thereof, and a recording medium. A display unit and a lens included in the display apparatus constitute a plurality of display optical systems each displaying a video for a left eye and a right eye of a user. The display apparatus includes a refractive power change instruction unit and a refractive power change driving unit capable of being used to change a refractive power related to the plurality of display optical systems, and an object position calculation unit for calculating an object position of a display object in the video. The refractive power change instruction unit gives a driving instruction to the refractive power change driving unit based on information acquired from a user information recording unit and an operation mode recording unit recording information about a usage status of the display apparatus.

Description

Technical Field

[0001] This invention relates to a technique for adjusting diopter in display devices. Background Technology

[0002] There are video display devices that are worn on a user's head, and video display devices that are worn on a user's body like glasses. The display units are arranged near the user's eyes and display parallax video for the user's right and left eyes respectively. When the user visually recognizes the displayed parallax video, a stereoscopic effect is obtained on the objects displayed in the parallax video.

[0003] Japanese Patent Application Publication No. 2006-195084 discloses a technique for reducing discomfort relative to displayed images and reducing motion sickness in observers during prolonged continuous use. Based on the condition of the user's eyes, image processing is performed to blur the portion of the displayed parallax video except for the part focused on the retina.

[0004] Incidentally, when a person views an object, the angle of convergence (the angle at which the lines of sight from both eyes intersect) and the focal length of the lens in the eyeball vary depending on the distance from the object to the eye. In real space, the relationship between the angle of convergence and the focal length of the lens remains essentially the same.

[0005] In the related technology disclosed in Japanese Patent Application Publication No. 2006-195084, the displayed parallax video represents the change in the position of an object, but the display position (diopter) of the parallax video in the optical axis direction of the video display device is always fixed. Therefore, when a user views an image of an object displayed as a parallax video, the user's convergence angle changes according to the position of the object. At this time, the focal length of the lens changes according to the size of the convergence angle based on experience in real space. In this case, there is a possibility that the focal length of the lens and the diopter of the video display device are inconsistent with each other. Therefore, it may not be possible to ensure good visibility for the user, for example, it may be difficult to clearly view the displayed parallax video due to defocusing.

[0006] Therefore, in adjusting the diopter of a video display device, it is preferable to change the diopter based on the position of an object in the parallax video used to determine the user's angle of convergence, using a method such as driving a lens in the device. However, due to factors such as age or visual acuity, the relationship between the user's angle of convergence and the focal length of the lens varies from person to person. If the diopter is changed uniformly based on the position of the displayed object in the parallax video on the video display device, some users may have difficulty clearly viewing the displayed parallax video due to the defocusing of the parallax video, and good visibility may not be guaranteed. Furthermore, the appropriate lens driving speed can vary depending on whether the video display device is in a normal mode that does not reduce power consumption or in a power-saving mode intended for long-term use. The appropriate diopter adjustment operation can vary based on differences including user differences (individual differences) and the usage conditions of the video display device's operating mode. Summary of the Invention

[0007] The present invention provides a display device capable of changing the diopter corresponding to the usage conditions.

[0008] According to an embodiment of the present invention, a display device includes a first display optical system and a second display optical system, wherein the first display optical system and the second display optical system are used to display video for the user's left and right eyes respectively. The display device includes a calculation unit and a diopter-changing unit, wherein the calculation unit is used to calculate the object position of a displayed object in the video displayed by the first display optical system and the second display optical system, and the diopter-changing unit is used to change the diopter associated with the first display optical system and the second display optical system based on information about the object position and information about the usage of the display device.

[0009] Further features of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a schematic diagram illustrating a illustrative configuration of the video display device in this embodiment.

[0011] Figure 2A and Figure 2B This is a schematic diagram showing the state of a moving lens in a video display device.

[0012] Figure 3 This is a schematic diagram illustrating an example of video data.

[0013] Figure 4 This is a schematic diagram illustrating the state of an observer viewing a video on a display unit through a lens.

[0014] Figure 5This is a schematic diagram showing the change in a user's diopter relative to the distance from an object.

[0015] Figure 6 This is a flowchart illustrating the operation of a video display device.

[0016] Figure 7 This is a schematic diagram illustrating the diopter change operation of a video display device. Detailed Implementation

[0017] In the following, embodiments of the invention will be described in detail with reference to the accompanying drawings. This embodiment describes an example of refractive power change control in a head-mounted or glasses-type video display device; however, the invention can be applied to various types of display devices capable of displaying parallax video. Note that parallax video is video with parallax, wherein parallax video consists of multiple images with different viewpoints.

[0018] Figure 1 This diagram illustrates a schematic configuration of the video display device 1 according to this embodiment. Details of each unit will be described later, and the video data acquisition unit 100, display processing unit 101, diopter change indication unit 106, object position calculation unit 108, user information recording unit 109, and operation mode recording unit 110 are implemented by one or more processors, such as a CPU, reading and executing programs. The video display device 1 can be used by being worn on a user's head or by being worn like glasses. In either form, the video display device 1 can be fixed near the user's left eye 2a and right eye 2b respectively. Note that this is distinguished by adding symbol 'a' to the reference numerals of the components associated with the user's left eye 2a and symbol 'b' to the reference numerals of the components associated with the user's right eye 2b.

[0019] The video display device 1 includes a video data acquisition unit 100 and a display processing unit 101. The video data acquisition unit 100 acquires video data for display via an external device or network. The display processing unit 101 performs display scaling adjustment processing on the acquired video data. The processed video data is sent to two display units 102a and 102b for display. For example, there is a configuration where the video data is divided into data for the two display units 102a and 102b and displayed. The present invention is not limited to this configuration, and a configuration in which the screen of one display unit is divided into two screens and the video data is displayed on two separate screens can also be adopted.

[0020] The video display device 1 includes a first display optical system and a second display optical system corresponding to the left eye 2a and the right eye 2b. The first display optical system includes a lens 103a, and the second display optical system includes a lens 103b. The video displayed on the display units 102a and 102b is presented to the left eye 2a and the right eye 2b through the corresponding lenses 103a and 103b.

[0021] The diopter-changing drive units 104a and 104b have a drive source such as a motor, and drive the lenses 103a and 103b respectively. That is, the diopter-changing drive units 104a and 104b move the lenses 103a and 103b in the direction along the optical axis of the lenses 103a and 103b (see arrows 104a1 and 104b1). In this embodiment, the description is given under the assumption that the optical axes 103a1 and 103b1 of the lenses 103a and 103b pass through the centers of the display units 102a and 102b and the eyes 2a and 2b, but this is not limiting.

[0022] Figure 2A and Figure 2B This diagram illustrates the state in which lenses 103a and 103b are moved by diopter-changing drive units 104a and 104b. Figure 2A This diagram shows the states in which lenses 103a and 103b are moved to the vicinity of display units 102a and 102b, respectively. Figure 2B This diagram illustrates the states where lenses 103a and 103b are moved to the vicinity of eyes 2a and 2b, respectively. When a user, acting as an observer, views display units 102a and 102b through lenses 103a and 103b with eyes 2a and 2b, the user visually recognizes virtual images 105a and 105b. The position of virtual images 105a and 105b in the direction of optical axes 103a1 and 103b1, with reference to the position of the observer's eyes 2a and 2b, is defined as virtual image forming position i.

[0023] like Figure 2A and Figure 2B As shown, the virtual image forming position i can be changed by altering the positions of lenses 103a and 103b. For example, when lenses 103a and 103b are close to display units 102a and 102b, the virtual image forming position i is close to eyes 2a and 2b. Conversely, when lenses 103a and 103b are close to eyes 2a and 2b, the virtual image forming position i is retracted relative to eyes 2a and 2b. Therefore, the diopter can be changed by moving lenses 103a and 103b using diopter-changing drive units 104a and 104b.

[0024] In this embodiment, a configuration has been described where lenses 103a and 103b are close to display units 102a and 102b and the virtual image forming position i is close to eyes 2a and 2b; however, the invention is not limited thereto. A configuration where lenses 103a and 103b are close to display units 102a and 102b and the virtual image forming position i is retracted relative to eyes 2a and 2b can also be used. Furthermore, a configuration has been described where lenses 103a and 103b are moved by diopter-changing drive units 104a and 104b to change diopter; however, the invention is not limited to the movement of optical components. For example, a configuration where display units 102a and 102b are moved by diopter-changing drive units 104a and 104b can be used. Additionally, an embodiment can be used where diopter-changing drive units 104a and 104b are configured using a method that does not involve movement of lenses 103a and 103b (e.g., using liquid lenses, etc.). Furthermore, the motor driving method in a configuration that uses a motor to change diopter is not limited; however, since the video display device is located near the observer's ear, a motor with high quietness is preferred for the video display device 1. For example, a voice coil motor or a vibration wave motor is preferred. Furthermore, in Figures 1 to 2B In the example shown, the number of individual lenses in lenses 103a and 103b is one, but the number of individual lenses in a lens can be two or more, or a configuration in which the positions of multiple lenses are moved when the diopter is changed can be adopted.

[0025] Figure 1 The diopter change indication unit 106 determines the amount of change in diopter relative to the position of the displayed object in the displayed video and provides an indication corresponding to the amount of change. Specifically, the diopter change indication unit 106 obtains information about the current virtual image forming position i from the diopter change driving units 104a and 104b, determines the next virtual image forming position i, and provides an indication to the diopter change driving units 104a and 104b. Here, the virtual image forming position i corresponds to the position of the lenses 103a and 103b, so the information about the current position of the lenses 103a and 103b can be used as the information about the current virtual image forming position i. In the case of a configuration where the display units 102a and 102b are moved, the information about the current position of the display units 102a and 102b can be used as the information about the current virtual image forming position i. As described above, the information about the relative position of the display units 102a and 102b with the lenses 103a and 103b can be used as the information about the current virtual image forming position i.

[0026] Reference Figure 3 Describe the video data. Figure 3This is a schematic diagram illustrating an example of video data 100D. The video data 100D consists of, for example, data of left-eye video 100a displayed on display unit 102a for the left eye and data of right-eye video 100b displayed on display unit 102b for the right eye.

[0027] Although this embodiment describes an example of video data 100D consisting of data from two videos 100a and 100b, the invention is not limited thereto. For example, a configuration can be used to generate parallax videos that are processed by display processing unit 101 based on three-dimensional data and displayed on each of the two display units 102a and 102b. Alternatively, data from video captured by a camera mounted on video display device 1 can be used as at least a portion of video data 100D. Using such a configuration, video display device 1 can display video in an augmented reality spatial representation. For example, video data 100D can be created by overlaying video captured by a camera mounted on video display device 1 with video based on pre-created three-dimensional data, and the composite video can be displayed.

[0028] like Figure 3 As shown, the data for displayed objects 107a and 107b are included in the data of the left-eye video 100a and the right-eye video 100b. In this embodiment, the case where the number of each displayed object 107a and 107b is one is described, but the invention is not limited thereto. For example, a configuration in which multiple objects are displayed in a video captured by a camera can be employed. In this case, for example, a gaze direction detection sensor capable of detecting the gaze direction of the user's eyes 2a and 2b is mounted on the device. Processing is performed to regard the object pointed to by the user's gaze as displayed objects 107a and 107b.

[0029] Figure 4 This is a schematic diagram illustrating how an observer visually views a displayed video through a lens. (Compared to...) Figure 3 The left-eye video 100a corresponding to the video data 100D shown is displayed on the display unit 102a for the left eye, and the right-eye video 100b is displayed on the display unit 102b for the right eye. An observer uses eyes 2a and 2b to observe the displayed videos on display units 102a and 102b through lenses 103a and 103b. At this time, as... Figure 4 As shown, virtual images 105a and 105b are reflected in the observer's eyes 2a and 2b. Display objects 107a and 107b are displayed in the virtual images 105a and 105b at positions Xa and Xb away from the optical axes 103a1 and 103b1 in directions perpendicular to the optical axes 103a1 and 103b1, respectively.

[0030] When an observer gazes at display objects 107a and 107b with eyes 2a and 2b respectively, eyes 2a and 2b rotate as indicated by arrows and face display objects 107a and 107b respectively. At this time, the optical axes 2a1 and 2b1 of the lenses of eyes 2a and 2b tilt to pass through display objects 107a and 107b respectively. The angle formed by optical axes 2a1 and 2b1 is called the convergence angle θ. In this state, display objects 107a and 107b fuse and appear as a single object to the observer. That is, display object 107c appears to exist at a virtual object position Z in the directions of optical axes 103a1 and 103b1, with the positions of eyes 2a and 2b as a reference. There is a correlation between the object position Z perceived by the observer's vision and the convergence angle θ, and humans perceive this correlation as a feeling derived from everyday experience. Therefore, when the observer (user) identifies the virtual object 107c as existing at position Z based on the convergence angle θ when the observer views the displayed objects 107a and 107b.

[0031] Figure 1 The object position calculation unit 108 shown can calculate the position of displayed objects 107a and 107b relative to optical axes 103a1 and 103b1 based on the distances Xa and Xb of these objects relative to the optical axes 103a1 and 103b1, which are associated with the video data 100D. Figure 4 The geometric calculations of the relationships shown are used to calculate the position Z of the virtual object.

[0032] Figure 1 The user information recording unit 109 and the operation mode recording unit 110 shown are examples of usage status recording units that record information about the usage status of the video display device 1 in a memory connected to the processor. Although examples of user information and operation mode information have been described in this embodiment, the present invention is not limited thereto, and various changes and modifications can be made without departing from the scope of the invention.

[0033] User information recording unit 109 can record user information. (Refer to...) Figure 5 Describe a specific example. Figure 5 It is a graph that schematically shows the change in the user's refractive power (horizontal axis) relative to the distance to the object (vertical axis). For example... Figure 5 As shown by line 501, a person's refractive power typically varies depending on the object's distance. When a person is viewing an object at a short distance, the refractive power changes to be adjusted to a near position, and conversely, when a person is viewing an object at a long distance, the refractive power changes to be adjusted to a far position. As a result, a person can see objects clearly regardless of whether they are at a short or long distance.

[0034] exist Figure 5In the case of the relationship between object distance and refractive power represented by line 501, the refractive power changes significantly with changes in object distance. On the other hand, in the case of the relationship between object distance and refractive power represented by line 502, the refractive power does not change much even when the object distance changes. This may be due to, for example, a decrease in the focusing ability of the eye's lens caused by aging. Therefore, in the case of young people, many tend to show the relationship represented by line 501, and in the case of middle-aged people, many tend to show the relationship represented by line 502. In the case of people showing the relationship represented by line 502, the range of object distances at which objects can be clearly viewed is narrow, and it is generally difficult to clearly view objects with long or short object distances. In the case of such people, by using glasses with different refractive powers depending on the viewing position (such as reading glasses), objects can be clearly viewed even when the object has a long or short object distance.

[0035] exist Figure 5 In the case of the relationship between object distance and refractive power represented by line 503, although the relationship between the change in object distance and the change in refractive power is the same as in the case of line 501, the refractive power at the same object distance is different. This is a situation where the object distance at which an object can be clearly viewed varies due to the influence of myopia or hyperopia. In such cases, glasses can usually be used to correct the relationship between object distance and refractive power as shown by line 501.

[0036] As described above, there are individual differences in a user's refractive power relative to object distance, and the amount of change in refractive power relative to object distance varies for each individual. The user information recording unit 109 records information based on the relationship between object distance and refractive power for each user. In the recording method, for example, display units 102a and 102b display refractive power measurements for different virtual object positions Z. The refractive power is changed by refractive power change driving units 104a and 104b, and processing is performed to record the positions of lenses 103a and 103b that match the refractive power with the virtual object position Z. Additionally, it is possible to roughly estimate whether the user's refractive power change is close to the characteristic represented by line 501 or line 502 based on age. For this purpose, for example, there is a method in which the user's age is input, and the data estimated based on the input age is recorded in the user information recording unit 109. Note that the method for recording the information to be recorded in the user information recording unit 109 is not limited to a specific method.

[0037] Figure 1The operation mode recording unit 110 shown can record the operation mode of the video display device 1. Specifically, the video display device 1 has a power-saving mode and a normal mode that does not reduce power consumption. The operation mode recording unit 110 records data indicating which of the two modes is set. Note that the above two modes are examples, and data from various operation modes can be recorded in the operation mode recording unit 110 as needed.

[0038] Reference Figure 6 The flowchart describes the operation of the video display device 1. When the video display in display units 102a and 102b is started by turning on the power supply of the video display device 1, etc., execution begins from S1. Figure 6 The flowchart is as follows. In S1, the object position calculation unit 108 calculates the virtual object position Z when the user views the displayed objects 107a and 107b related to the video data 100D with eyes 2a and 2b.

[0039] In S2, the diopter change indication unit 106 calculates appropriate operation indication information for the diopter change operation performed by the diopter change driving units 104a and 104b. At this time, the information of the virtual object position Z calculated in S1, the user information recorded in the user information recording unit 109, and the operation mode recording unit 110 are used.

[0040] The user information used in S2 is based on, for example, such as Figure 5 The information shown relates to the object distance and diopter in relation to the user. The diopter change indication unit 106 calculates indication information for the diopter change operation performed by the diopter change driving units 104a and 104b based on the relationship between the object distance and diopter in relation to the user.

[0041] Figure 7 This is a graph showing the relationship between the virtual object's position Z (vertical axis) and the diopter of the video display device 1 calculated by the diopter change indicator unit 106 (horizontal axis). For example, suppose it has a... Figure 5 The first user represents the characteristic indicated by line 501 in the diagram. In this case, operational instructions are given for the diopter-changing drive units 104a and 104b to obtain the diopter-changing characteristics. Figure 7 The characteristic represented by line 701 in the diagram. Additionally, in a configuration with... Figure 5 In the case of the second and third users, represented by lines 502 and 503, operation instructions are given for the diopter-changing drive units 104a and 104b to obtain the characteristics of the second and third users, respectively. Figure 7The characteristics are represented by lines 702 and 703. Therefore, in the case of the second user, the range of diopter change of the video display device 1 becomes narrower than in the case of the first user. Furthermore, in the case of the third user, the range of diopter change of the video display device 1 is the same as that of the first user, but the diopter is different when the virtual object position Z is the same. By performing diopter change operation according to the user in this way, even when the amount of change in diopter relative to the object distance is different for each user, the appropriate diopter can be clearly displayed regardless of the differences between users.

[0042] In addition, Figure 6 The operating mode information used in S2 is the operating mode information recorded in the operating mode recording unit 110. In S2, the speed during the driving of the diopter-changing drive units 104a and 104b changes according to the operating mode, so that the diopter is set based on the virtual object position Z and user information. When the operating mode recorded in the operating mode recording unit 110 is the normal mode, the diopter-changing drive units 104a and 104b change the diopter at the maximum speed that can be driven. On the other hand, when the operating mode recorded in the operating mode recording unit 110 is the power-saving mode, the diopter-changing drive units 104a and 104b change the diopter at a lower speed than the driving speed in the normal mode. When the driving speed used to change the diopter is low, timing of diopter mismatch occurs, which may lead to a display incongruity. In order to suppress the display incongruity, it is preferable to increase the driving speed used to change the diopter as much as possible. On the other hand, to increase the driving speed for changing the diopter, lenses 103a and 103b need to be driven at a high speed, which requires more power. Therefore, in normal mode, the diopter is changed at a higher driving speed to suppress display inconsistencies as much as possible. Furthermore, in power-saving mode, some display inconsistencies are allowed, and the diopter is changed at a lower driving speed than in normal mode, which consumes less power. In other words, the driving time for changing the diopter can be controlled to adjust according to the operating mode. With this configuration, appropriate driving can be achieved based on the usage of the video display device 1.

[0043] In this embodiment, a configuration has been described in which operational control is performed to appropriately change the refractive power using both user information and operating mode. The invention is not limited to this, and the following configurations can also be adopted in which operational control is performed to appropriately change the refractive power based on either user information or operating mode. For example, the drive speed for changing the refractive power can be changed based on user information, or the drive speed for changing the refractive power can be set lower when the refractive power change range is narrow than when the refractive power change range is wide. Additionally, the following configurations can be adopted in which operational control is performed to change the refractive power relative to the virtual object position Z based on information other than user information and operating mode.

[0044] exist Figure 6 In step S3, the diopter change instruction unit 106 provides instructions to each of the diopter change drive units 104a and 104b for the diopter change operation determined in step S2, and operates the diopter change drive units 104a and 104b. The diopter of the video display device 1 is changed by driving the lenses 103a and 103b. Next, in step S4, in response to the instruction from the display processing unit 101, the display units 102a and 102b display the video corresponding to the video data 100D.

[0045] In this embodiment, the display processing of display units 102a and 102b is performed in S4 after the diopter change operation is performed in S3. However, the invention is not limited to this, and a configuration in which S3 and S4 are performed simultaneously or S4 is performed before S3 can also be used.

[0046] Using the above configuration, diopter adjustment based on the virtual object's position Z can be appropriately performed according to the usage of the video display device 1 (such as differences between users and operating modes). Appropriate diopter adjustment can be achieved regardless of the usage of the video display device 1 (such as individual differences in the relationship between object distance and diopter (which differs for each user) and differences in the operating mode of the video display device 1). According to this embodiment, even when users are different, the display can be clear regardless of the virtual object's position Z, and the video display device 1 can be used for extended periods depending on the usage. Note that user information (i.e., information related to the usage of the video display device 1) can be input by the user or an external device each time the video display device is used.

[0047] Although preferred embodiments of the invention have been described above, the invention is not limited to these embodiments, and various modifications and changes can be made within the scope of its spirit.

[0048] Other embodiments

[0049] Various embodiments of the present invention can also be implemented by a computer of a system or device that reads and executes computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more fully referred to as a "non-transitory computer-readable storage medium") to perform one or more functions of the above embodiments and / or includes one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing one or more functions of the above embodiments, and by the following method, wherein the computer of the system or device performs the above method by, for example, reading and executing computer-executable instructions from the storage medium to perform one or more functions of the above embodiments and / or controlling the one or more circuits to perform one or more functions of the above embodiments. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessor unit (MPU)) and may include a network of separate computers or separate processors to read and execute the computer-executable instructions. These computer-executable instructions may, for example, be provided to the computer from a network or storage medium. The storage medium may include, for example, hard disks, random access memory (RAM), read-only memory (ROM), the memory of a distributed computer system, optical discs (such as CDs, DVDs, or Blu-ray discs). TM One or more of the following: flash storage devices and memory cards.

[0050] While the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be given the broadest interpretation to cover all such modifications and equivalent structures and functions.

[0051] This application claims the benefit of Japanese Patent Application 2021-138310, filed on August 26, 2021, the entire contents of which are incorporated herein by reference.

Claims

1. A display device comprising a first display optical system and a second display optical system for displaying video for a user's left and right eyes respectively, the display device comprising: The calculation unit is used to calculate the object position of the displayed object in the video displayed by the first display optical system and the second display optical system; as well as A diopter-changing unit is used to change the diopter based on information about the object's position and information about the amount of change in diopter relative to the object distance related to the first display optical system and the second display optical system. The diopter-changing unit uses the information about the amount of diopter change related to the first display optical system and the second display optical system to determine the rate of diopter change when changing the diopter.

2. The display device according to claim 1 further includes a recording unit for recording information on the amount of change in the diopter relative to the distance from the object.

3. The display device according to claim 1, wherein, The diopter changing unit determines the amount of change in diopter relative to the distance from the object.

4. The display device according to claim 3, wherein, The diopter changing unit uses information about the amount of change in diopter relative to the distance from the object to determine the amount of change.

5. The display device according to any one of claims 1 to 4, wherein, The first display optical system and the second display optical system display video with parallax.

6. A control method executed by a display device, the display device comprising a first display optical system and a second display optical system for displaying video for a user's left and right eyes respectively, the control method comprising: Calculate the object position of the displayed object in the video displayed by the first display optical system and the second display optical system; The diopter is changed based on information about the object's position and information about the amount of change in diopter relative to the object distance associated with the first and second display optical systems. as well as Using the information regarding the amount of change in refractive power associated with the first display optical system and the second display optical system, the rate of change of refractive power when the refractive power is changed is determined.

7. A non-transitory recording medium storing a control program that causes a computer to perform steps of a control method for a display device, the display device including a first display optical system and a second display optical system for displaying video for a user's left and right eyes respectively, the control method comprising: Calculate the object position of the displayed object in the video displayed by the first display optical system and the second display optical system; The diopter is changed based on information about the object's position and information about the amount of change in diopter relative to the object distance associated with the first and second display optical systems. as well as Using the information regarding the amount of change in refractive power associated with the first display optical system and the second display optical system, the rate of change of refractive power when the refractive power is changed is determined.

8. A computer program product comprising a control program that causes a computer to perform steps of a method for controlling a display device, the display device including a first display optics system and a second display optics system for displaying video for a user's left and right eyes respectively, the control method comprising: Calculate the object position of the displayed object in the video displayed by the first display optical system and the second display optical system; The diopter is changed based on information about the object's position and information about the amount of change in diopter relative to the object distance associated with the first and second display optical systems. as well as Using the information regarding the amount of change in refractive power associated with the first display optical system and the second display optical system, the rate of change of refractive power when the refractive power is changed is determined.

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