Lens control device, lens device for eyes, eyeglasses, control method, and program

Abstract

To ensure that, when the focal length of a variable-focal length lens is automatically controlled to a target focal length (conforming focal length) in accordance with the distance to an object to be visually recognized, the wearer hardly feels glaring and damage to the eye retina is mitigated even when strong light enters the eyes of the wearer through the variable-focal length lens.SOLUTION: Provided is a lens control device for controlling the focal length of a variable-focal length lens for eyes, the device including a control unit for controlling the focal length of the variable-focal length lens so as to become equal to a target focal length conforming to the distance to the object to be visually recognized that is detected by a distance detection unit. When the detection result of a light detection unit that detects the intensity of light entering the eyes of the wearer via the variable-focal length lens exceeds a prescribed threshold (Yes in S16), the control unit changes the focal length of the variable-focal length lens to another focal length that deviates from the target focal length (S17).SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a lens control device, an ophthalmic lens device, glasses, a control method, and a program. [Background technology]

[0002] Patent Document 1 discloses a lens control device that automatically controls the focal length of a variable-focus lens to a suitable focal length (target focal length) suited to a user in accordance with the visible distance to an object to be viewed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-040850 A Summary of the Invention [Problem to be solved by the invention]

[0004] With this type of lens control device, when strong light enters the user's eye through a variable focus lens, the function of automatically controlling the focal length of the variable focus lens to an appropriate focal length (target focal length) can cause issues such as the light being more dazzling and more likely to damage the retina than with non-variable focus lenses such as ordinary glass lenses. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, one aspect of the present invention is a lens control device that controls the focal length of a variable focus lens for the eye, and has a control unit that controls the focal length of the variable focus lens so that it becomes a target focal length corresponding to the distance to a viewed object detected by a distance detection unit, and is characterized in that when the detection result of a light detection unit that detects the intensity of light entering the wearer's eye through the variable focus lens exceeds a predetermined threshold, the control unit changes the focal length of the variable focus lens to another focal length that deviates from the target focal length. In this lens control device, the focal length of the variable-focus lens is controlled to a target focal length (for example, an appropriate focal length at which the wearer can see the object in focus when viewing the object) according to the distance to the object detected by the distance detection unit. In this case, even if the distance to the object changes, the focal length of the variable-focus lens is automatically controlled to the appropriate focal length for the wearer according to the distance. This allows the wearer to see both nearby and distant objects in an automatically focused state without performing any special operation. However, with such automatic control of the focal length of a variable-focus lens, the light incident on the wearer's eye is focused near the retina of the eye regardless of the distance at which the wearer views an object. Therefore, when such automatic control is being performed, for example, if the wearer views an object that emits strong light (such as the sun or a lighting fixture), the strong light enters the wearer's eye through the variable-focus lens and is focused on the retina of the eye. As a result, the wearer may feel more dazzled or be more susceptible to damage to the retina than in the case of a non-variable-focus lens such as a general glass lens. In this lens control device, when the detection result of the light detection unit that detects the intensity of light entering the wearer's eye through the variable-focus lens exceeds a predetermined threshold, the focal length of the variable-focus lens is changed to another focal length that is different from the target focal length (suitable focal length). With this, even if strong light (light whose detection result of the light detection unit exceeds a predetermined threshold) enters the wearer's eye through the variable-focus lens, the focusing position of the light entering the eye can be moved away from the retina or its vicinity, compared to when the focal length of the variable-focus lens remains automatically controlled to the target focal length (suitable focal length). This makes it possible to make the wearer less likely to feel glare and reduce damage to the retina.

[0006] In the lens control device, the diopter equivalent value of the different focal length may be a negative value. According to this, when strong light enters the wearer's eye through the variable-focus lens, the light entering the eye is diffused as it passes through the variable-focus lens whose focal length has been changed to another one. This makes it possible to more reliably prevent the light entering the eye from concentrating on the retina or its vicinity, and it is possible to reliably obtain the effects of making the wearer less likely to feel glare and reducing damage to the retina.

[0007] In the lens control device, the different focal length may be a lower limit value of a focal length control range of the variable-focus lens. According to this, when strong light enters the eye of the wearer through the variable-focus lens, the light entering the eye can be diffused to the maximum extent possible when passing through the variable-focus lens whose focal length has been changed to another focal length. This makes it possible to more reliably prevent the light entering the eye from concentrating on or near the retina of the eye, and can reliably obtain the effects of making the wearer less likely to feel glare and reducing damage to the retina of the eye.

[0008] Another aspect of the present invention is an eye lens device comprising a variable focus lens for the eye, a distance detection unit which detects the distance to an object to be viewed, and a lens control device which controls the focal length of the variable focus lens so that it becomes a target focal length corresponding to the distance to the object to be viewed detected by the distance detection unit, characterized in that it comprises a light detection unit which detects the intensity of light entering the wearer's eye through the variable focus lens, and uses the above-mentioned lens control device as the lens control device. The present ophthalmic lens device can be used as an article that is worn by a wearer, such as glasses or contact lenses. By using the present ophthalmic lens device as an article worn by a wearer in this way, even if the wearer sees a visual object that emits strong light (the sun, lighting equipment, etc.) during daily life while wearing the article (for example, while watching TV, playing games, using a computer or tablet, reading a book, etc.), the wearer is less likely to feel dazzled and damage to the retina of the eye can be reduced.

[0009] Yet another aspect of the present invention is a pair of spectacles comprising the above-mentioned ophthalmic lens device, the variable focus lens being held in a spectacle frame. If the ophthalmic lens device is used as glasses, as described above, even if the wearer sees a visual object that emits strong light (the sun, lighting equipment, etc.) in daily life while wearing the glasses, the wearer can feel less dazzled and damage to the retina of the eye can be reduced. Also, if it is glasses, the configuration of the lens control device can be arranged in the glasses frame that holds the variable focus lens, and the connection configuration between the variable focus lens and the variable focus lens control device can be simplified, making it possible to reduce costs.

[0010] Yet another aspect of the present invention is a control method for controlling the focal length of a variable-focus lens for an eye, comprising a control step of controlling the focal length of the variable-focus lens to a target focal length corresponding to the distance to a visual object detected by a distance detection unit, wherein the control step is characterized in that when the detection result of a light detection unit that detects the intensity of light entering the wearer's eye through the variable-focus lens exceeds a predetermined threshold value, the focal length of the variable-focus lens is changed to another focal length that deviates from the target focal length. According to this control method, as in the case of the lens control device described above, even if the wearer sees an object that emits strong light (the sun, lighting equipment, etc.), the wearer is less likely to feel dazzled and damage to the retina can be reduced.

[0011] Yet another aspect of the present invention is a program that causes a computer of a lens control device to function, which controls the focal length of a variable-focus lens for the eye so that it becomes a target focal length corresponding to the distance to a visual object detected by a distance detection unit, and is characterized in that when the detection result of a light detection unit that detects the intensity of light entering the wearer's eye through the variable-focus lens exceeds a predetermined threshold, the program causes the computer to function as a control means that changes the focal length of the variable-focus lens to another focal length that deviates from the target focal length. According to this program, as in the case of the lens control device described above, even if the wearer views an object that emits strong light (the sun, lighting fixtures, etc.), the wearer is less likely to feel dazzled and damage to the retina can be reduced. Effect of the Invention

[0012] According to the present invention, when the focal length of a variable-focus lens is automatically controlled to a target focal length (suitable focal length) according to the distance to an object to be viewed, even if strong light enters the wearer's eye through the variable-focus lens, the wearer is less likely to feel dazzled and damage to the retina of the eye can be reduced. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a front view showing a schematic configuration of eyeglasses according to an embodiment. [Diagram 2] FIG. 2 is a plan view showing a schematic configuration of the glasses. [Diagram 3] FIG. 2 is a cross-sectional view showing a schematic configuration of a variable focus lens in the eyeglasses. [Figure 4] FIG. 2 is a plan view showing a schematic configuration of a variable focus lens in the eyeglasses. [Diagram 5] FIG. 2 is a block diagram showing the configuration of a control device in the glasses. [Figure 6] FIG. 4 is an explanatory diagram showing an example of table data that is focal length specification information stored in a storage unit of the control device; [Figure 7] 5 is a flowchart showing an example of a setting mode of focal length control in the embodiment. [Figure 8] 5 is a flowchart showing an example of a use mode of focal length control in the embodiment. [Figure 9] 6 is a graph for explaining an approximation formula calculated from the table data. [Figure 10] FIG. 11 is a front view showing a schematic configuration of glasses according to another embodiment. [Figure 11] FIG. 1 is a perspective view showing an example of the appearance of glasses according to an embodiment. [Figure 12]FIG. 2 is an exploded perspective view of the eyeglasses of the same external appearance example with the lens cover removed. [Figure 13] FIG. [Figure 14] FIG. [Figure 15] FIG. [Figure 16] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment in which the present invention is applied to spectacles as an ophthalmic lens device equipped with a lens control device will be described. The ophthalmic lens device to which the present invention can be applied is not limited to spectacles, but may be other items worn by a wearer (hereinafter referred to as a "user").

[0015] FIG. 1 is a front view showing a schematic configuration of eyeglasses 1 according to the present embodiment, and FIG. 2 is a plan view showing a schematic configuration of eyeglasses 1 according to the present embodiment. The glasses 1 in this embodiment include a glasses frame 2, a pair of left and right variable focus lenses 3,3, and a control device 10 as a lens control device that controls the focal length of the variable focus lenses 3,3.

[0016] The eyeglass frame 2 includes a bridge portion 4, a pair of left and right lens holding portions 6, 6, a nose pad portion 7, a pair of left and right end pieces 8, 8, and a pair of left and right temple portions 9, 9.

[0017] The bridge portion 4 is disposed at a position above the field of vision of the wearer when worn, and is a member supporting the left and right lens holding portions 6,6 that hold the variable focus lenses 3,3. The bridge portion 4 extends in the left-right direction between the left and right end pieces 8,8, and the end pieces 8,8 are attached to both left and right ends of the bridge portion 4. The bridge portion 4 preferably includes an inter-lens distance adjustment portion that connects the lens holding portions 6 so that the lens holding portions 6 are movable in the left-right direction, and can adjust the inter-lens distance D in the left-right direction of the pair of left and right variable focus lenses 3,3 held by the lens holding portions 6. The inter-lens distance D can be determined, for example, by the distance between reference positions on the variable focus lenses 3,3 (for example, the center positions of the variable focus lenses 3,3). Here, the reference position of the variable focus lenses 3,3 is equal to, for example, the optical center position of the variable focus lenses 3,3, and the inter-lens distance D is equal to the distance between the optical centers of the variable focus lenses 3,3.

[0018] The lens holders 6, 6 are members that hold the variable-focus lenses 3, 3, and have an elongated (linear) shape. Specifically, the lens holders 6, 6 in this embodiment are formed of a wire member that can be plastically deformed. The lens holder 6 in this embodiment extends from the bridge portion 4 in the eyeglass frame 2, and its tip is connected to the connected position 3a of the outer edge portion of the variable-focus lens 3, thereby holding the variable-focus lens 3. The lens holder 6 is supported by the bridge portion 4 via the slide portion 4a, and the slide portion 4a constitutes a lens distance adjustment portion. Specifically, the slide portion 4a is a member that holds the lens holder 6 slidably in the left-right direction relative to the bridge portion 4. The slide portion 4a in this embodiment is a hollow member, and the bridge portion 4 is inserted into the hollow portion and attached to the bridge portion 4 so as to be slidable along the longitudinal direction of the bridge portion 4.

[0019] By providing an inter-lens distance adjustment unit, the inter-lens distance D of the variable-focus lenses 3,3 can be adjusted to match the inter-pupillary distance PD of the user in a normal viewing state. When the variable-focus lenses 3,3 are smaller than normal eyeglass lenses as in this embodiment, it is beneficial to be able to adjust the inter-lens distance D of the variable-focus lenses 3,3 for each user to match the user's inter-pupillary distance PD.

[0020] In this embodiment, the connected positions 3a of the variable-focus lenses 3,3 to which the lens holding parts 6,6 are connected are located outside (the side farther from the nose, i.e., toward the ear) of a vertical imaginary line passing through the optical axis of the variable-focus lenses 3,3, as shown in Fig. 1, and located above a horizontal imaginary line passing through the optical axis of the variable-focus lenses 3,3. By configuring the lens holding parts 6,6 to be connected at these positions, the lens holding parts 6,6 are unlikely to be perceived as an obstacle even if they are within the field of vision of the wearer.

[0021] However, the connected position 3a of the variable focus lens 3,3 to which the lens holding portion 6,6 is connected is not limited to the position in this embodiment, and may be positioned, for example, inside (toward the nose) a vertical imaginary line passing through the optical axis of the variable focus lens 3,3, as shown in Figure 10.

[0022] The nose pads 7 are held by the bridge portion 4 and are members that position the spectacles 1 by coming into contact with the user's nose when the user wears the spectacles 1.

[0023] The end fitting portions 8, 8 are members that connect the bridge portion 4 and the temple portions 9, 9. In this embodiment, the end fitting portions 8, 8 include an attachment portion 8a that is attached to an end portion of the bridge portion 4, and a hinge portion 8b that rotatably supports the temple portion 9.

[0024] The temples 9, 9 are members that are hung on the ears of the user when the user wears the eyeglasses 1. In this embodiment, the left and right temples 9, 9 are configured so that they can be folded toward the center of the eyeglasses 1 in the left-right direction by the hinges 8b provided on the end pieces 8, 8.

[0025] The variable-focus lens 3,3 in this embodiment is not limited to this configuration as long as it has an electrically controllable focal length changing function. However, the variable-focus lens 3,3 is preferably a shape-variable lens whose focal length changes by changing the shape of the refracting surface. Among shape-variable lenses, a liquid lens (also called an electrowetting device, etc.) whose focal length can be changed by using the interface between two types of liquid as the refracting surface and electrically controlling the wettability of the liquid to change the shape of the interface is preferable. A liquid lens allows high-speed and highly flexible control of the focal length.

[0026] The variable-focus lenses 3, 3 of this embodiment are liquid lenses with a lens portion having a diameter of, for example, about 5 mm to 12 mm. By using a larger variable-focus lens, the range of the user's line of sight that the variable-focus lens can cover can be expanded, improving user convenience.

[0027] FIG. 3 is a cross-sectional view showing a schematic configuration of the variable-focus lens 3 in this embodiment. FIG. 4 is a plan view showing a schematic configuration of the variable-focus lens 3 in this embodiment. As shown in Fig. 3, the variable-focus lens 3 of this embodiment has a configuration in which an insulating liquid 311 and a conductive liquid 312, which are in contact with each other in an unmixed state at an interface I, are sealed between an annular first electrode 301 and two transparent window members 303 and 304 that close the upper and lower ends of the first electrode 301. The insulating liquid 311 is, for example, an oil-based liquid, and the conductive liquid 312 is, for example, an aqueous liquid with a relatively low conductivity. A voltage V0 is applied to the first electrode 301, but in this embodiment, since the annular first electrode 301 is grounded, V0 = 0V. The first electrode 301 is insulated from the sealed insulating liquid 311 and conductive liquid 312 by an insulating layer 301a.

[0028] Furthermore, in the variable-focus lens 3 of this embodiment, a plurality of pairs of second electrodes 302A, 302B, ... are arranged at symmetrical positions with respect to the axis O of the first electrode 301. In this embodiment, as shown in Fig. 4, four pairs of second electrodes 302A to 302H are arranged on a circumference centered on the axis O, and a total of eight second electrodes 302A to 302H are provided.

[0029] 3, the second electrodes 302A-302H are disposed at positions in contact with the conductive liquid 312. When voltages VA-VH are applied to the second electrodes 302A-302H, a potential difference is generated between the second electrodes 302A-302H and the first electrode 301, and the end Ia of the insulating liquid 311 (the end Ia of the interface I) can be displaced along the insulating layer portion 301b on the first electrode 301 by the electrowetting effect. By displacing the end Ia of the insulating liquid 311 in this way, the shape of the insulating liquid 311 changes, and the curvature of the interface I is changed. Therefore, by controlling the voltages VA-VH applied to the second electrodes 302A-302H, the focal length of the variable-focus lens 3 having the interface I as a refracting surface can be changed.

[0030] In particular, the variable-focus lens 3 of this embodiment can change the interface I, which is a refractive surface, into a diffusing lens (concave lens), a flat lens, or a condensing lens (convex lens) by controlling the voltages VA to VH applied to the second electrodes 302A to 302H. Therefore, the glasses 1 of this embodiment can be used as glasses for myopic users by making the variable-focus lens 3 a diffusing lens (concave lens), and can be used as glasses for hyperopic users by making the variable-focus lens 3 a condensing lens (convex lens).

[0031] The variable-focus lens 3 of this embodiment can change the focal length in a range of -15 D to +15 D in diopter conversion (the reciprocal of the focal length). By using the variable-focus lens 3 with such a wide range of focal length change, it is possible to accommodate users with low vision, such as those with amblyopia.

[0032] In this embodiment, by applying the same voltage to all of the second electrodes 302A-302H arranged at symmetrical positions with respect to the axis O of the first electrode 301, it is possible to change the focal length while keeping the optical axis of the variable-focus lens 3 aligned with the axis O of the first electrode 301. On the other hand, by applying different voltages to the second electrodes 302A-302H, it is possible to not only change the focal length but also shift or tilt the optical axis of the variable-focus lens 3. That is, the variable-focus lens 3 of this embodiment can change either the position or the direction of the optical axis, or both, by controlling the applied voltages VA-VH.

[0033] 1, the control device 10 is provided in one of the left and right end pieces 8, 8 (the end piece 8 on the right side (left side in the figure)) together with the battery 20. The control device 10 can control the focal length of the variable-focus lens 3 by controlling the voltage applied from the battery 20 to each of the second electrodes 302A-302H of the variable-focus lens 3.

[0034] FIG. 5 is a block diagram showing the configuration of the control device 10 in this embodiment. The control device 10 in this embodiment includes a main control unit 11, a voltage changing unit 12, an operation unit 13, and a storage unit 14. The control device 10 is connected to second electrodes 302A-302H of the two variable-focus lenses 3,3, a battery 20 as a power source that supplies voltage, a distance detection unit 21 that detects the distance to an object visually recognized by the user through the variable-focus lenses 3,3, and an illuminance detection unit 22 as a light detection unit that detects the intensity of light incident on the user's eyes through the variable-focus lenses 3,3.

[0035] The main control unit 11 is configured by, for example, a control board (computer) equipped with a CPU, RAM, ROM, etc., and performs overall control of the eyeglasses 1, which is an ophthalmic lens device, by executing a predetermined control program stored in the ROM. Particularly in this embodiment, the main control unit 11 functions as a control unit (control means) that controls the variable-focus lenses 3,3 so that the focal length of the variable-focus lenses 3,3 changes based on the visible distance (detection result) to the visible object detected by the distance detection unit 21.

[0036] The voltage changing unit 12, under the control of the main control unit 11, changes the voltage applied from the battery 20 to each of the second electrodes 302A-302H of the variable-focus lens 3. The voltage changing unit 12 can change the voltage applied to each of the second electrodes 302A-302H individually for each of the second electrodes 302A-302H. However, the voltage changing unit 12 may be capable of partially changing only a part of the second electrodes 302A-302H (for example, only one pair of second electrodes).

[0037] When operated by a user, the operation unit 13 outputs an operation signal indicating the user's operation to the main control unit 11. Examples of user operations accepted by the operation unit 13 include power on / off operations, execution instructions for the main control unit 11, and changes to the control contents of the main control unit 11. In particular, the operation unit 13 in this embodiment accepts user operations for changing the focal lengths of the two variable-focus lenses 3,3.

[0038] The operation unit 13 is configured with an operation device of a type suitable for the content of the user operation to be accepted (such as a mechanical or electrostatic touch button, or a rotary operation unit such as a dial). The operation unit 13 of this embodiment is configured with two rotary operation dial units 13a, 13a and a button operation button unit 13b.

[0039] The rotary dial units 13a, 13a are provided on the sides of the left and right end pieces 8, 8, respectively, as shown in Figures 1 and 2, and are configured to be rotatable around a rotary axis extending in the left-right direction. The dial unit 13a provided on the left end piece 8 accepts an instruction to shorten the focal length of the left-eye variable-focus lens 3 when rotated counterclockwise, and accepts an instruction to lengthen the focal length of the left-eye variable-focus lens 3 when rotated clockwise. The dial unit 13a provided on the right end piece 8 accepts an instruction to shorten the focal length of the right-eye variable-focus lens 3 when rotated clockwise, and accepts an instruction to lengthen the focal length of the right-eye variable-focus lens 3 when rotated counterclockwise.

[0040] The button section 13b of the button operation type is provided on the rotation axis of the dial section 13a provided on the right end piece 8, and accepts user instruction operations by pushing the dial section 13a along the rotation axis in the direction of the arrow A in Figures 1 and 2. In this embodiment, the button section 13b accepts switching operations for switching the operation mode of the main control section 11, user decision instruction operations, and the like.

[0041] In this embodiment, the switching operation by the button unit 13b is an operation for switching between a setting mode and a use mode. The setting mode is an operation mode for setting focal length specification information used in the use mode, and sets a suitable focal length for the user according to the visible distance detected by the distance detection unit 21. The use mode is an operation mode for automatically controlling the focal length of the variable-focus lenses 3,3 to a suitable focal length according to the visible distance detected by the distance detection unit 21.

[0042] In this embodiment, the user's decision instruction operation using the button section 13b is, for example, performed by operating the dial sections 13a, 13a to change the focal length of each variable-focus lens 3, 3, searching for (measuring) a focal length that suits the user, and performing a decision instruction operation when the suitable focal length is determined.

[0043] The storage unit 14 stores programs and data used by the control device 10. In particular, in this embodiment, focal length specification information for specifying the focal length of the variable-focus lenses 3,3 according to the distance to a visual target is stored as data used for controlling the focal length of the variable-focus lenses 3,3 in the use mode.

[0044] The focal length specification information is, for example, information indicating the relationship between the visible distance to the visual target (the detection result of the distance detection unit 21) and each focal length of the two variable-focus lenses 3,3 corresponding to each visible distance (a focal length suited to the user corresponding to each visible distance). Such information can be stored in the storage unit 14 as table data describing the correspondence between the visible distance and the focal length of the two variable-focus lenses 3,3, for example, as shown in FIG.

[0045] In particular, in this embodiment, the focal length specification information includes measurement information that measures the focal lengths (suitable focal lengths) of the two variable-focus lenses 3, 3 that are suitable for a user according to the visual distance to a visual target object. This allows the focal lengths of the two variable-focus lenses 3, 3 to be adjusted to appropriate focal lengths for each user in the usage mode.

[0046] The battery 20 functions as a power source for the control device 10, and outputs a voltage to be supplied to the second electrodes 302A to 302H of the variable-focus lens 3. The battery 20 may be a primary battery or a secondary battery. In addition, the battery 20 may be equipped with a power generation function, such as a solar panel.

[0047] The configuration of the distance detection unit 21 is not limited as long as it can detect the distance to a visual object present in the area (visual recognition area) in front of the variable focus lenses 3, 3, but it is preferable that the distance detection unit 21 is disposed on the eyeglass frame 2, particularly in the vicinity of the variable focus lenses 3, 3. The distance detection unit 21 in this embodiment is disposed on the nose pad 7 as shown in Fig. 1, but may also be disposed on the bridge portion 4 or end piece portions 8, 8. However, since it is preferable that the distance detection unit 21 is disposed in a position where it is least likely to be covered by hair (bangs) when the user wears the eyeglasses 1, it is preferable to dispose it as low as possible on the front of the eyeglasses 1 (on the nose pad 7) as in this embodiment.

[0048] The distance measurement method in distance detection unit 21 is not particularly limited, and a wide variety of existing distance measurement methods can be adopted, such as a laser method, a sound wave method, etc. If it is difficult for one distance detection unit to cover the range of visible distances (range from close to long distances) to be detected by distance detection unit 21, multiple distance detection units with different effective detection distance ranges (distance ranges in which highly accurate detection is possible) may be arranged.

[0049] The illuminance detection unit 22 detects the illuminance in the area (visible area) in front of the variable focus lens 3,3, but the configuration is not limited as long as it can detect the intensity of light incident on the user's eye through the variable focus lens 3,3. However, in order to detect the intensity of light incident on the user's eye through the variable focus lens 3,3, the illuminance detection unit 22 is configured so that its detection area includes the area visually recognized by the user through the variable focus lens 3,3.

[0050] It is preferable that the illuminance detection unit 22 is configured so as to be able to be placed on the eyeglass frame 2. In this embodiment, the illuminance detection unit 22 is placed on the nose pad 7 as shown in Fig. 1, but it may also be placed on the bridge portion 4 or the end piece portions 8, 8. However, it is preferable that the illuminance detection unit 22 is placed in a position where it is unlikely to be covered by hair (bangs) when the user wears the eyeglasses 1.

[0051] Next, an example of control of the focal length of the variable-focus lenses 3, 3 in this embodiment will be described. Figures 7 and 8 are flowcharts showing the flow of focal length control in this embodiment, where Figure 7 shows the control content in the setting mode, and Figure 8 shows the control content in the use mode. In the focal length control of this embodiment, in the usage mode, the main control unit 11, which executes a predetermined control program, controls the voltage changing unit 12 to control the focal length of the variable focus lenses 3, 3 based on the visible distance (detection result) to the visible object detected by the distance detection unit 21 and the focal length specification information in the memory unit 14.

[0052] In this embodiment, when the operation unit 13 receives a power-on operation by the user (S1), first, a switching operation to switch the operation mode of the main control unit 11 to a setting mode or a use mode is received (S2). Specifically, if the button unit 13b is pressed within a predetermined time after the power-on operation, the operation mode transitions to the setting mode (Yes in S2), and if the button unit 13b is not pressed within the predetermined time, the operation mode transitions to the use mode (No in S2). Note that, although this is an example in which focal length control is started by the power-on operation, the present invention is not limited to this. For example, a wearing detection unit that detects that the eyeglasses 1 are worn by the user may be provided, and the focal length control may be started by detecting that the eyeglasses 1 are worn by the user.

[0053] When the mode is changed to the setting mode (Yes in S2), the main control unit 11 executes a program for operating in the setting mode. In the setting mode, the user first rotates the left dial unit 13a while viewing an object at a reference viewing distance (for example, a long distance) (Yes in S3). As a result, an operation signal is sent from the operation unit 13 to the main control unit 11, and the main control unit 11 controls the voltage change unit 12 so that a voltage corresponding to the operation signal is applied to the second electrodes 302A to 302H of the variable-focus lens 3 for the left eye. As a result, the curvature of the interface I between the insulating liquid 311 and the conductive liquid 312 in the variable-focus lens 3 for the left eye is changed due to a change in shape of the interface I, and the focal length of the variable-focus lens 3 for the left eye is changed in response to the user's operation on the left dial unit 13a (S4).

[0054] Then, after adjusting the focal length of the left-eye variable-focus lens 3 by turning the left dial unit 13a so that the object at the reference distance is brought into focus, the user then turns the right dial unit 13a while viewing the object at the same reference distance (Yes in S5). This causes an operation signal to be sent from the operation unit 13 to the main control unit 11, and the main control unit 11 controls the voltage change unit 12 so that a voltage corresponding to the operation signal is applied to the second electrodes 302A to 302H of the right-eye variable-focus lens 3. This causes a change in the shape of the interface I between the insulating liquid 311 and the conductive liquid 312 in the right-eye variable-focus lens 3 to change the curvature of the interface I, and the focal length of the right-eye variable-focus lens 3 is changed in response to the user's operation on the right dial unit 13a (S6). Then, the user turns the right dial unit 13a to adjust the focal length of the right-eye variable-focus lens 3 so that the object at the reference distance is brought into focus.

[0055] In this way, after adjusting the focal lengths of the left and right variable-focus lenses 3,3 by turning the left and right dial units 13a,13a so that the visual object at the reference distance is in focus, the user presses the button unit 13b (Yes in S7). The main control unit 11, which has received this button operation signal, acquires the detection result of the visual distance detected by the distance detection unit 21 for the visual object at the above-mentioned reference distance (S8). Then, the main control unit 11 stores the focal lengths of the left and right variable-focus lenses 3,3 at the time when the button unit 13b is pressed and the acquired detection result of the visual distance as focal length specification information in the memory unit 14 (S9).

[0056] For example, if the detection result of the visible distance detected by the distance detection unit 21 is d10, the main control unit 11 adds d10 as the visible distance data in the table data shown in Fig. 6. Then, the main control unit 11 stores fL10 and fR10, which are the focal lengths (suitable focal lengths) adjusted by the user, as the focal lengths of the left and right variable-focus lenses 3, 3 corresponding to the visible distance d10.

[0057] When executing the use mode, it is desirable to set the user's suitable focal length for a larger number of visibility distances. The user can set the user's suitable focal length (fL1, fL6, fL10, fR1, fR6, fR10 in FIG. 6) for multiple visibility distances (three points, d1, d6, d10 in FIG. 6) by repeating the operation of changing the visibility distance to the visual target and executing the setting mode described above.

[0058] Next, the use mode will be described. If the button section 13b is not pressed within a predetermined time after the power-on operation, or if the setting mode ends, the mode transitions to the use mode shown in Fig. 8 (S10). When the mode transitions to the use mode, the main control section 11 first starts a detection operation by the illuminance detection section 22 (S11). This causes the illuminance detection section 22 to detect the intensity (illuminance) of light incident on the user's eyes through the variable focus lenses 3, 3 of the glasses 1. This detection operation is repeatedly executed at a predetermined sampling interval. The detection result of the illuminance detected by the illuminance detection section 22 is sent to the main control section 11, and the main control section 11 performs eye protection control, which will be described later, based on the detection result of the illuminance.

[0059] Furthermore, when the mode is shifted to the use mode, the main control unit 11 calculates an approximation formula as shown in the graph in FIG. 9 from the focal length specification information (for example, the table data shown in FIG. 6) stored in the storage unit 14 (S12). This approximation formula is a formula that indicates the relationship between the visibility distance detected by the distance detection unit 21 and the suitable focal length for the user at that visibility distance, and is a formula that indicates an approximation line when the focal length specification information (table data) stored in the storage unit 14 is plotted as shown in FIG. 9. For example, the least squares method or Hough transform can be used to calculate the approximation formula. Note that, although this embodiment is an example in which the table data used to calculate the approximation formula is stored in the storage unit 14 as the focal length specification information, the approximation formula may also be stored in the storage unit 14 as the focal length specification information.

[0060] After calculating the approximation formula in this way, the main control unit 11 acquires the detection result of the visible distance from the distance detection unit 21 to the visual target (S13). After that, the main control unit 11 derives the suitable focal length corresponding to the acquired visible distance (detection result) by the approximation formula calculated in the processing step S11 (S14). Then, the main control unit 11 controls the voltage change unit 12 to change the voltage applied to the second electrodes 302A to 302H of the left and right variable-focus lenses 3,3 so that the focal lengths of the left and right variable-focus lenses 3,3 become the derived suitable focal lengths. As a result, the focal lengths of the left and right variable-focus lenses 3,3 are changed to the focal lengths suitable for the user (S15), and the visual target is automatically brought into focus.

[0061] For example, when a user views a nearby visual object (such as a smartphone, tablet, game console, or book), the focal lengths of the left and right variable-focus lenses 3,3 are automatically changed to focus on the nearby visual object. Also, for example, when a user views a distant visual object (such as a video (movie, etc.) from a distant location, an object of appreciation such as a work of art, or a landscape), the focal lengths of the left and right variable-focus lenses 3,3 are automatically changed to focus on the distant visual object. Also, for example, when a user views a medium-distance visual object such as while driving a car, the focal lengths of the left and right variable-focus lenses 3,3 are automatically changed to focus on the medium-distance visual object.

[0062] Here, when the focal length of the variable-focus lenses 3,3 is automatically controlled as in this embodiment, the light incident on the user's eye is focused near the retina of the eye regardless of the distance of the visual object. Therefore, when such automatic control is performed, for example, if the user visually recognizes a visual object that emits strong light (the sun, lighting equipment, etc.), the strong light is incident on the user's eye through the variable-focus lenses 3,3 and is focused on the retina of the eye. As a result, the user may feel more dazzled or more susceptible to damage to the retina than in the case of a non-variable-focus lens such as a general glass lens.

[0063] Therefore, in this embodiment, the main control unit 11 judges whether or not the detection result (illuminance) of the illuminance detection unit 22, which can grasp the intensity of light incident on the user's eyes through the variable-focus lenses 3,3, exceeds a predetermined threshold value (upper threshold value) during execution of the use mode (S16). Then, when it is judged that the detection result (illuminance) of the illuminance detection unit 22 exceeds the upper threshold value (Yes in S16), the main control unit 11 executes eye protection control to change the focal length of the variable-focus lenses 3,3 to another focal length (predetermined focal length for eye protection) that is different from the suitable focal length (target focal length) controlled by the automatic control (S17).

[0064] Specifically, the main control unit 11 controls the voltage changing unit 12 to apply a voltage corresponding to the eye-protection focal length to each of the second electrodes 302A to 302H of the variable-focus lens 3. The upper limit threshold can be set appropriately depending on the intensity of light to be prevented from entering the user's eyes.

[0065] In the above-mentioned eye protection control, the diopter equivalent value of the eye protection focal length may be a positive value (e.g., +10D), but is preferably a negative value (e.g., -10D). According to this, when strong light is incident on the user's eye through the variable-focus lens 3,3, the light incident on the eye is diffused when passing through the variable-focus lens 3,3 whose focal length has been changed to the eye protection focal length. This makes it possible to more stably prevent the light incident on the eye from being concentrated on the retina of the eye or in the vicinity thereof, and stably obtain the effects of making the user less likely to feel dazzled and reducing damage to the retina of the eye.

[0066] In particular, the eye protection focal length is preferably the lower limit of the focal length control range of the variable-focus lens 3,3. With this, when strong light is incident on the user's eye through the variable-focus lens 3,3, the light incident on the eye can be diffused to the maximum extent possible when passing through the variable-focus lens 3,3 whose focal length has been changed to the eye protection focal length. This makes it possible to more stably prevent the light incident on the eye from being concentrated on or near the retina of the eye, and stably obtain the effects of making the wearer less likely to feel glare and reducing damage to the retina of the eye.

[0067] As described above, the variable-focus lens 3,3 of this embodiment can change the focal length in a range of diopter conversion from -15D to +15D. Therefore, the eye-protection focal length is set to -15D (diopter conversion), which is the lower limit of the focal length control range of the variable-focus lens 3,3.

[0068] In this embodiment, when the operation unit 13 accepts a power-off operation by the user (Yes in S15), the main control unit 11 ends the focal length control. At this time, the voltage supply to each of the second electrodes 302A-302H of the variable-focus lens 3 may be turned off or on. If the voltage supply to each of the second electrodes 302A-302H of the variable-focus lens 3 is turned off, the power consumption of the battery 20 can be saved.

[0069] According to this embodiment, even if strong light (light whose detection result of the illuminance detection unit 22 exceeds the upper limit threshold) enters the user's eye through the variable-focus lens 3,3 during use mode, the focal position of the light entering the eye can be moved away from the retina or its vicinity, compared to when the focal length of the variable-focus lens 3,3 remains automatically controlled to the focal length suited to the user. This makes it possible to make the user less likely to feel dazzled and reduce damage to the retina.

[0070] 11 to 16 show examples of the appearance of the glasses 1 according to this embodiment. In addition, the same reference numerals are used to designate the various components corresponding to those described in the above embodiment.

[0071] The eyeglasses 1 of this external appearance example are provided with a lens cover 5 arranged to cover the front of the variable focus lenses 3, 3. The lens cover 5 is preferably one that ensures visibility such that the user can visually recognize a visual object present in a forward area (visualization area) through the variable focus lenses 3, 3.

[0072] In the eyeglasses 1 of this external appearance example, the operation unit 13 is composed of one rotary dial unit 13a and two button units 13b, 13b. In this configuration, the focal length of the right-eye variable-focus lens 3 can be adjusted by operating the button unit 13b located near the right end piece 8 and then rotating the dial unit 13a (S3 to S4). After adjusting the focal length of the right-eye variable-focus lens 3, the user presses the button unit 13b located near the right end piece 8 (Yes in S7), and the detection result of the visible distance to the visual target is acquired (S8), and the focal length of the right-eye variable-focus lens 3 and the acquired detection result of the visible distance are stored in the storage unit 14 as focal length identification information (S9).

[0073] Similarly, the focal length of the left-eye variable-focus lens 3 can be adjusted by operating the button unit 13b located near the left end piece 8 and then turning the dial unit 13a (S5 to S6). After adjusting the focal length of the left-eye variable-focus lens 3, the user presses the button unit 13b located near the left end piece 8 (Yes in S7), and the detection result of the visible distance to the visual target is acquired (S8), and the focal length of the left-eye variable-focus lens 3 and the acquired detection result of the visible distance are stored in the memory unit 14 as focal length identification information (S9).

[0074] Additionally, the process steps and components of an ophthalmic lens device, such as the eyeglasses 1, described herein may be implemented by various means. For example, the steps and components may be implemented in hardware, firmware, software, or a combination thereof.

[0075] With regard to hardware implementations, the processing units or other means used to realize the steps and components described above may be implemented in one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processors (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units, computers designed to perform the functions described herein, or combinations thereof.

[0076] Also, for firmware and / or software implementations, the means such as processing units used to realize the components may be implemented with programs (e.g., codes such as procedures, functions, modules, instructions, etc.) that execute the functions described herein. In general, any computer / processor readable medium tangibly embodying firmware and / or software codes may be used to implement the means such as processing units used to realize the steps and components described herein. For example, the firmware and / or software codes may be stored in a memory and executed by a computer or processor, for example in a controller. The memory may be implemented within the computer or processor, or may be implemented externally to the processor. Also, the firmware and / or software codes may be stored in a computer or processor readable medium, such as a random access memory (RAM), a read-only memory (ROM), a non-volatile random access memory (NVRAM), a programmable read-only memory (PROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, a floppy disk, a compact disk (CD), a digital versatile disk (DVD), a magnetic or optical data storage device, etc. The code may be executed by one or more computers or processors and may cause the computers or processors to perform certain aspects of the functionality described herein.

[0077] The medium may be a non-transitory recording medium. The code of the program may be in any format as long as it can be read and executed by a computer, a processor, or another device or machine, and the format is not limited to a specific format. For example, the code of the program may be any of source code, object code, and binary code, or may be a mixture of two or more of these codes. [Explanation of symbols]

[0078] 1: Glasses 2: Eyeglass frames 3: Variable focus lens 4: Bridge section 4a: Slide section 6: Lens holder 7:Nose part 8: Armor section 8a: Mounting part 8b: Hinge part 9: Temple section 10: Control device 11: Main control unit 12: Voltage change section 13:Operation section 13a: Dial section 13b: Button section 13c: Lever section 14: Storage section 20: Battery 21: Distance detection unit 22: Illuminance detection unit 301:First electrode 301a, 301b: insulating layer 302A~302H: Second electrode 303, 304: Window materials 311: Insulating liquid 312: Conductive liquid D: Lens distance I: Interface Ia: End O :Axis PD: pupillary distance

Claims

1. A lens control device for controlling a focal length of a variable-focus lens for an eye, comprising: a control unit that controls a focal length of the variable-focus lens so that the focal length becomes a target focal length according to a distance to a visual target detected by a distance detection unit; The control unit changes the focal length of the variable-focus lens to another focal length deviating from the target focal length when a detection result of a light detection unit that detects the intensity of light entering the wearer's eye through the variable-focus lens exceeds a predetermined threshold.

2. 2. The lens control device according to claim 1, The lens control device according to claim 1, wherein the diopter equivalent value of the different focal length is a negative value.

3. 3. The lens control device according to claim 2, The lens control device according to claim 1, wherein the different focal length is a lower limit value of a focal length control range of the variable-focus lens.

4. A variable focus lens for the eye; A distance detection unit that detects a distance to a visually recognized object; a lens control device that controls a focal length of the variable-focus lens so that the focal length becomes a target focal length corresponding to a distance to a visual object detected by the distance detection unit, a light detection unit that detects the intensity of light incident on the wearer's eye through the variable focus lens; An ophthalmic lens device, comprising a lens control device according to any one of claims 1 to 3 as the lens control device.

5. An ophthalmic lens device according to claim 4, The variable focus lens is held in a spectacle frame.

6. 1. A method for controlling a focal length of a variable focus lens for an eye, comprising: a control step of controlling a focal length of the variable-focus lens so that the focal length becomes a target focal length according to a distance to a visually recognized object detected by a distance detection unit; A control method characterized in that, in the control step, when a detection result of a light detection unit that detects the intensity of light entering the wearer's eye through the variable-focus lens exceeds a predetermined threshold, the focal length of the variable-focus lens is changed to another focal length deviating from the target focal length.

7. A program for causing a computer of a lens control device to function that controls a focal length of a variable-focus lens for an eye so that the focal length becomes a target focal length according to a distance to a visual object detected by a distance detection unit, A program that causes the computer to function as a control means that changes the focal length of the variable-focus lens to another focal length that is different from the target focal length when the detection result of a light detection unit that detects the intensity of light entering the wearer's eye through the variable-focus lens exceeds a predetermined threshold.

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