Device for preventing lowering of eyesight by using display device and method for preventing lowering of eyesight

Abstract

To provide a device for preventing the lowering of eyesight and asthenopia of a user by using a display device such as a portable terminal.SOLUTION: A device for preventing the lowering of eyesight of the present invention is provided in a display device having a front camera provided on a surface side on which a display screen is present. The device for preventing the lowering of eyesight includes: a congestion state measuring device that measures a congestion state of eyes of a user who views the display screen of the display device; an alert unit that issues a predetermined alert; and an alert instruction determination unit that compares the congestion state measured by the congestion state measuring device with an alert congestion state stored in advance and instructs the alert unit to issue an alert when it is determined that a predetermined condition is satisfied.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a device or method for preventing vision loss, eye strain, and the like caused by the use of display devices such as personal computers and mobile terminals such as tablets and smartphones.

[0002] It has been known that prolonged use of a display device reduces the number of times the eyes blink, which can lead to dry eyes, eye strain, and decreased vision. For this reason, there are devices that measure whether or not the display device in use measures the number of times the user blinks, and restricts use of the display device in certain cases (Patent Document 1).

[0003] In addition to blinking, deterioration of eyesight due to the use of display devices can also occur when using a display device for long periods of time. For this reason, one way to prevent eye strain is to look at something more than 20 feet away for 20 seconds after looking at a display screen for 20 minutes (the 20-20-20 rule). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-25445 Summary of the Invention [Problem to be solved by the invention]

[0005] However, particularly with mobile terminals that are held in the hand to view display images, the display device tends to be viewed closer and closer to the eyes during use, which can lead to a decrease in eyesight and eye strain.

[0006] Therefore, as a result of various studies, the inventors have focused on eye convergence, and have come up with a method for determining the state of the eyes from this convergence (convergence state) and preventing deterioration of eyesight and the like. [Means for solving the problem]

[0007] The device for preventing vision loss due to the use of a mobile terminal of the present invention is a device for preventing vision loss that is installed in a display device having a front camera installed on the side where the display screen is located, and is characterized in that the device for preventing vision loss comprises a convergence state measuring device that measures the eye convergence state of a user looking at the display screen of the display device, an alert unit that issues a predetermined alert, and an alert instruction judgment unit that compares the convergence state measured by the convergence state measuring device with a pre-stored alert congestion state, and instructs the alert unit to issue an alert if it determines that a predetermined condition is met.

[0008] Further, the convergence state is the convergence angle of the user's eyes, and the convergence state measuring device comprises a pupil direction measuring device section that measures the direction of the left and right pupils as seen from the display screen, and a convergence angle calculation device section that calculates the angle between the pupils of the left eye and the right eye as seen from the display screen from the measured pupil direction, and the predetermined condition is characterized in that the calculated convergence angle is determined to be equal to or greater than a pre-stored alert convergence angle.

[0009] Further, the convergence state is the convergence angle of the user's eyes, and the convergence state measuring device comprises a pupil direction measuring device section that measures the direction of the left and right pupils as seen from the display screen, and a convergence angle calculation device section that calculates the angle between the pupils of the left eye and the right eye as seen from the display screen from the measured pupil direction, and the predetermined condition is that the calculated convergence angle is determined to be equal to or greater than a pre-stored alert convergence angle for a predetermined period of time or more.

[0010] Further, the convergence state is the convergence angle of the user's eyes, and the convergence state measuring device comprises a screen distance measuring device unit that measures the screen distance between the display screen and the user's eyes, and a convergence angle calculation unit that calculates the convergence angle from the interpupillary distance between the user's left and right eyes and the screen distance measured by the screen distance measuring device unit, and the predetermined condition is characterized in that the calculated convergence angle is determined to be equal to or greater than a pre-stored alert convergence angle.

[0011] Further, the convergence state is the convergence angle of the user's eyes, and the convergence state measuring device comprises a screen distance measuring device unit that measures the screen distance between the display screen and the user's eyes, and a convergence angle calculation unit that calculates the convergence angle from the interpupillary distance between the user's left and right eyes and the screen distance measured by the screen distance measuring device unit, and the predetermined condition is characterized in that the calculated convergence angle is determined to be equal to or greater than a pre-stored alert convergence angle for a predetermined period of time or more.

[0012] The alert convergence angle is characterized in that an alert convergence angle determination unit provided in the convergence state measurement device calculates a reference convergence angle from a preset screen distance and the interpupillary distance of the user at that screen distance using the convergence angle calculation unit, and then the alert convergence angle is calculated from the calculated reference convergence angle.

[0013] The interpupillary distance is calculated by an image processing unit through image processing of an image captured by the front camera.

[0014] The display device is also characterized by further comprising a storage unit for storing the time (VDT time) that the user views the display screen.

[0015] Further, the convergence state is the screen distance between the display screen and the user's eyes, the convergence state measuring device comprises a screen distance measuring device unit that measures the screen distance, and the predetermined condition is when the measured image distance is determined to be equal to or less than a pre-stored alert screen distance.

[0016] Further, the convergence state is the screen distance between the display screen and the user's eyes, the convergence state measuring device comprises a screen distance measuring device unit that measures the screen distance, and the predetermined condition is when the measured image distance is determined to be equal to or less than a pre-stored alert screen distance for a predetermined period of time or more.

[0017] The convergence state is the interpupillary distance between the left and right eyes of the user, the convergence state measuring device is an interpupillary measurement device that measures the interpupillary distance of the user, and the predetermined condition is that the measured interpupillary distance is determined to be equal to or less than a pre-stored interpupillary distance.

[0018] The convergence state is the interpupillary distance between the left and right eyes of the user, the convergence state measuring device is an interpupillary measurement device that measures the interpupillary distance of the user, and the predetermined condition is when the measured interpupillary distance is determined to be equal to or less than a pre-stored interpupillary distance for a predetermined period of time or more.

[0019] Furthermore, the method for preventing vision loss of the present invention is characterized in that the eye convergence state of a user looking at a display screen of a display device having a front camera provided on the side where the display screen is located is measured by a convergence state measuring device provided on the display device, and an instruction judgment unit provided on the display device compares the measured convergence state with a pre-stored alert congestion state, and if it is determined that a predetermined condition is met, an alert is issued to an alert unit of the display device. [Effects of the Invention]

[0020] According to the present invention, deterioration of vision, eyestrain, etc. are determined based on convergence, so that deterioration of vision and eyestrain can be more effectively prevented. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is an explanatory diagram of a display device included in the device for preventing eyesight deterioration of the present invention. [Figure 2] 1 is an explanatory diagram of a device for preventing vision loss according to the present invention; [Figure 3] 10A and 10B are explanatory diagrams of another embodiment of the device for preventing vision loss of the present invention. [Figure 4] 10 is an explanatory diagram of still another embodiment of the device for preventing vision loss of the present invention. FIG. [Figure 5] 10 is an explanatory diagram of still another embodiment of the device for preventing vision loss of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention will now be described with reference to the drawings. [Example]

[0023] (1. Description of the overall configuration of the device for preventing vision loss)

[0024] As shown in Figures 1 and 2, the present invention is a vision deterioration prevention device 2 that is provided in a display device 1 that has a front camera 1b provided on the side where the display screen 1a is located, such as a personal computer or a mobile terminal such as a tablet or smartphone. The vision deterioration prevention device 2 comprises a convergence state measurement device 3 that calculates the convergence state of the left and right eyes of a user looking at the display screen 1a of the display device 1, and an alert instruction judgment unit 4 that compares the convergence state calculated by the convergence state measurement device 3 with a pre-stored alert congestion state and instructs the alert unit to issue an alert when it determines that a predetermined condition is met, by comparing the convergence state calculated by the convergence state measurement device 3 with a pre-stored alert congestion state.

[0025] Reference numeral 5 denotes a calculation and storage unit that performs calculations and storage so that various devices included in the display device 1, such as the display screen 1a of the display device 1 and the front camera, operate.

[0026] Furthermore, the congestion state measuring device 3 and the alert instruction determining unit 4 may be configured, in whole or in part, by computer programs (applications), and provided in the arithmetic and memory unit 5. Note that a device that is connected to the display device 1 separately may be used, in whole or in part.

[0027] The convergence state includes, for example, the convergence angle (the angle formed by the left eye and the right eye when viewed from the display screen (which is a concept that includes the front camera, and the same applies hereinafter)).

[0028] The convergence state measuring device 3 is a convergence angle calculation device, which is composed of, for example, a pupil direction measuring device section 3a that measures the direction of the left and right pupils as seen from the display screen, and a convergence angle calculation device section 3b that calculates the angle formed by the pupils of the left eye and the right eye as seen from the display screen from the measured pupil direction (calculates from the angle formed), and the convergence angle calculation device measures the convergence angle.

[0029] The above-mentioned convergence angle measuring device may be configured as a commercially available device capable of measuring the convergence angle of a user, or part or all of it may be configured by, for example, a computer program (application), and there are no particular limitations as long as it is an application that can calculate the convergence angle of the user's left and right eyes. For example, the above-mentioned front camera may capture images of the user's left and right eyes, and from the captured images, the directions of the left and right pupils as seen from the front camera may be calculated, and the angles formed by the calculated directions with the left and right eyes as seen from the front camera may be calculated to determine the convergence angles.

[0030] Furthermore, for example, the pupil direction measuring device section 3a may be provided in the display device 1 separately from a commercially available device capable of measuring angles, rather than as a computer program.

[0031] In addition to measuring the directions of the left and right pupils to calculate the convergence angle, the convergence angle calculation device may also be configured to include, for example, as shown in FIG. 3, a screen distance measurement device unit 3c that measures the screen distance between the display screen 1a and the user's eyes (the midpoint between the left and right pupils), and a convergence angle calculation device unit 3d that calculates the convergence angle (calculate from the screen distance) using a formula described later from the interpupillary distance between the user's left and right eyes (the distance between the centers of the pupils of the left and right eyes) and the screen distance measured by the screen distance measurement device unit 3c, and the convergence angle may be measured by the convergence angle calculation device.

[0032] The screen distance measurement device section 3c may be, for example, a commercially available distance measurement device that uses laser light or the like provided in the display device, or may use a commercially available computer program.

[0033] The screen distance may be calculated, for example, by capturing an image of the user's left and right eyes with the front camera, and calculating from the captured image the distance between the front camera and the part of the face corresponding to the midpoint between the left and right pupils, or the shortest distance between the front camera and the face.

[0034] The alert instruction determination unit 4 is composed of a determination unit 4a that compares the congestion state such as the convergence angle and determines whether or not the predetermined condition is met, and an instruction unit 4b that instructs the alert unit to display an alert, etc., when the determination unit 4a determines that the predetermined condition is met.

[0035] In addition to the display screen and speaker unit (including the earphone unit), the alert unit may also include a lighting unit provided on the display device 1 and a vibrating main body, and alerts may include, for example, the display of characters or figures on the display screen 1a, sounds, lighting or flashing lights, vibration of the display device main body, etc.

[0036] The above alert also includes a case where the screen is not displayed.

[0037] In addition to issuing the alert when a predetermined condition is met, the alert may be issued intermittently for a predetermined period of time, such as the time required for rest, or at intervals, or may be issued again at the end of the predetermined period of time.

[0038] (2. Explanation of vergence angle calculation)

[0039] When calculating the convergence angle from the interpupillary distance and screen distance, the formula "convergence angle △ (prism) = 100 × interpupillary distance (cm) ÷ screen distance between the display screen and the eyes (cm)" and the formula "1 △ (prism) = 0.57°" are used to calculate "convergence angle (°) = 100 × interpupillary distance (cm) ÷ screen distance between the display screen and the eyes (cm) × 0.57°".

[0040] The interpupillary distance between the left and right eyes of the user used in calculating the convergence angle may be a predetermined value, such as 6.5 cm, which is the average interpupillary distance for adults, or 5 cm, which is the average interpupillary distance for children, for adults. However, other values ​​may also be used.

[0041] If the screen distance is, for example, 20 cm, the convergence angle can be calculated from the above formula to be 18° for adults and 14° for children.

[0042] If the screen distance is 20 cm, this may lead to a decrease in eyesight, so the alert convergence angle is set, for example, to 17° for adults and 13° for children, with reference to the above convergence angle value. However, this is not limited to these values. The same value may also be used for adults and children.

[0043] In addition to using the average interpupillary distance of the eyes of an average person as a reference for the interpupillary distance between the left and right eyes of the user, for example, as shown in Figure 4, the convergence state measuring device 3 may be provided with an interpupillary distance calculation unit 3e, and the image processing unit of the interpupillary distance calculation unit 3e may use the image captured by the front camera and perform image processing on the image to determine the interpupillary distance of the user.

[0044] The method of calculating the interpupillary distance by image processing in the image processing unit is, for example, to identify the pupil in the captured image by image processing, and calculate the distance between the left and right by treating the pupil as a circle and the center of the circle as the center of the pupil. However, the method is not limited to this as long as the interpupillary distance can be measured.

[0045] The interpupillary distance may be measured in real time, and the convergence angle may be calculated in real time.

[0046] It is also possible to set a predetermined value among the measured interpupillary distances as the interpupillary distance, and calculate the convergence angle based on this set value.

[0047] For example, the value measured when the display device is first used or before use may be regarded as the interpupillary distance, and this value may be used as the interpupillary distance whenever the user uses the display device. Alternatively, the interpupillary distance measured at a reference screen distance, which will be described later, may be used.

[0048] (3. Explanation of specified conditions)

[0049] Furthermore, the specified condition is determined from the relationship between the calculated convergence angle and a pre-stored alert convergence angle, for example, whether the calculated convergence angle is equal to or greater than a pre-stored alert convergence angle.

[0050] As the alert convergence angle, for example, as described above, a convergence angle that may cause a decrease in eyesight, etc. The alert convergence angle may be stored in accordance with the interpupillary distance.

[0051] Alternatively, as shown in FIG. 5, a separately provided alert convergence angle determination unit 6 may set a reference screen distance at which no convergence is considered to occur (however, this includes cases where convergence occurs), such as a screen distance at which there is no convergence, or a predetermined screen distance even if there is a possibility of a convergence state, for example, a screen distance of 30 cm or more, or the screen distance when the hand is stretched out as far as possible and is farthest from the display screen, or the screen distance when the user starts use, or the screen distance at which the hand is farthest during use.The reference screen distance may then be set to a predetermined interpupillary distance or a convergence angle calculated from the interpupillary distance measured by the interpupillary distance measurement unit at this reference screen distance, and the alert convergence angle may be set to a value obtained by multiplying the reference convergence angle by a predetermined magnification (a magnification greater than 1), for example, 110%, or may be set to an alert ventral angle. Alternatively, the alert ventral angle may be set to an angle obtained by adding a predetermined angle (positive angle) to the reference convergence angle, for example, +1°.

[0052] In addition, the relationship between the interpupillary distance and the screen distance that leads to a decrease in vision, etc. may be stored separately, and the screen distance that leads to a decrease in vision, etc. may be calculated from the measured interpupillary distance of the user and the above relationship, and the convergence angle at this screen distance may be set as the alert convergence angle and stored.

[0053] Furthermore, as the above-mentioned predetermined condition, for example, the alert instruction determination unit 4 may further be provided with a timer unit (not shown) that measures time, and the alert congestion angle may be set to a condition where the alert congestion angle remains for a predetermined time, for example, 20 minutes or more.

[0054] The timer section may be a built-in timer section provided in the arithmetic and memory section 5 of the display device 1.

[0055] Furthermore, the predetermined time may be a cumulative time other than a continuous time.

[0056] The alert convergence angle may have a different value depending on whether the desired time is taken into consideration or not.

[0057] Furthermore, the alert convergence angle may be divided into a plurality of angles in stages, and a predetermined time may be set for each of the divided alert convergence angles.

[0058] Also, an alert may be issued when the sum of the product of the alert convergence angle at each stage and the time during which the alert convergence angle at the corresponding stage has been reached exceeds a predetermined amount.

[0059] In addition, the above-mentioned eyesight deterioration prevention device may be provided with a separate storage device (not shown), or the calculation storage device 5 of the display device 1 may be used to store the above-mentioned captured images during monitoring, the screen distance, the interpupillary distance, the number of alerts, and VDT (Visual Display Terminals) time, etc., so that various information such as VDT time for one day or one week can be output as necessary.

[0060] Next, a method for using the present invention will be described.

[0061] As an initial setting of the device for preventing eyesight deterioration, the device for preventing eyesight deterioration stores an alert convergence angle and, if necessary, the predetermined time for the alert convergence angle for issuing an alert.

[0062] In addition, the interpupillary distance of the user, which is necessary for calculating the convergence angle, is stored as needed. Note that, when the interpupillary distance of the user is calculated in real time, it is possible to omit storing the interpupillary distance.

[0063] In addition, the above-mentioned predetermined conditions are set.

[0064] The user may be allowed to change the initial value.

[0065] When a user uses a mobile terminal or the like, the convergence angle is calculated constantly or periodically by the convergence angle measuring device, for example.

[0066] Furthermore, when the convergence angle is calculated using the screen distance and the interpupillary distance, the screen distance measuring device unit measures the image distance constantly or periodically, and the convergence angle calculation unit 3b calculates the user's convergence angle constantly or periodically from the image distance and the user's interpupillary distance stored in advance by the convergence angle calculation unit or the interpupillary distance calculated by the interpupillary distance calculation unit.

[0067] Then, when the calculated convergence angle is determined by the judgment unit 4a to satisfy the predetermined condition, the alert unit will, for example, display predetermined characters on the display screen or emit a sound from the speaker unit.

[0068] Then, for example, an alert may be issued again after a preset rest period has elapsed.

[0069] If necessary, various information such as VDT time can be stored in the storage unit and output as necessary.

[0070] According to the present invention, deterioration of vision, eyestrain, etc. are determined based on convergence, so that deterioration of vision and eyestrain can be more effectively prevented. [Example]

[0071] In a second embodiment of the present invention, the convergence state may be, for example, the screen distance between the display screen and the user's eyes, and the convergence state measuring device may be a screen distance measuring device unit that measures the screen distance, and issue an alert when it is determined that the measured image distance is equal to or less than a pre-stored alert screen distance.

[0072] Furthermore, an alert may be issued when the measured image distance is determined to be equal to or less than a pre-stored alert screen distance for a predetermined period of time or more.

[0073] The same parts as those in the first embodiment have the same configuration.

[0074] The alert screen distance can be set to various values, such as 20 cm or 10 cm, which may cause congestion.

[0075] The usage time may also be changed depending on the alert screen distance.

[0076] In this case, the deterioration of eyesight, eye strain, etc. are also judged, so that the deterioration of eyesight and eye strain can be prevented more effectively. [Example]

[0077] In a third embodiment of the present invention, the convergence state may be, for example, the interpupillary distance between the left and right eyes of the user, and the convergence state measuring device may be an interpupillary measurement device that measures the interpupillary distance of the user, and may issue an alert when it is determined that the measured interpupillary distance is equal to or less than a pre-stored interpupillary distance.

[0078] Furthermore, an alert may be issued if the measured interpupillary distance is determined to be equal to or smaller than a pre-stored interpupillary distance for a predetermined period of time or longer.

[0079] The same parts as those in the first embodiment have the same configuration.

[0080] As the alert interpupillary distance, in addition to storing in advance an interpupillary distance that may result in a decrease in vision, etc., the user's interpupillary distance can be measured at a screen distance that is thought to be unaffected by convergence, for example, at a relatively large screen distance, and this can be used as the reference interpupillary distance.Based on this reference interpupillary distance, the alert interpupillary distance can be set to, for example, a numerical value at a predetermined reduction rate (for example, 90%), or the value obtained by subtracting a predetermined distance (for example, 0.5 cm) from the numerical value.

[0081] In this case, the deterioration of eyesight, eye strain, etc. are also judged, so that the deterioration of eyesight and eye strain can be prevented more effectively. [Explanation of symbols]

[0082] 1 Display device 1a Display Screen 1b Front camera 2 Visual deterioration prevention device 3. Congestion state measurement device 3a Pupil direction measuring device section 3b Vergence angle calculation unit 3c Screen distance measuring device section 3D convergence angle calculation unit 3e Pupillary distance calculation section 4. Alert instruction decision unit 4a Judgment part 4b Instruction part 5 Arithmetic memory section 6 Alert convergence angle determination unit

Claims

1. A vision loss prevention device provided in a display device having a front camera provided on a side where a display screen is located, The device for preventing vision loss includes: a convergence state measuring device for measuring the convergence state of the eyes of a user who is viewing the display screen of the display device; an alert unit that issues a predetermined alert; an alert instruction determination unit that compares the congestion state measured by the congestion state measurement device with a pre-stored alert congestion state, and instructs the alert unit to issue an alert when it determines that a predetermined condition is satisfied; A device for preventing vision loss, comprising:

2. the convergence state is a convergence angle of the user's eyes, The convergence state measuring device comprises a pupil direction measuring device section that measures the directions of the left and right pupils as seen from the display screen, and a convergence angle calculating device section that calculates the angle between the pupils of the left eye and the pupils of the right eye as seen from the display screen from the measured pupil directions, 2. The device for preventing eyesight deterioration according to claim 1, wherein the predetermined condition is that the calculated convergence angle is determined to be equal to or greater than a pre-stored alert convergence angle.

3. the convergence state is a convergence angle of the user's eyes, The convergence state measuring device comprises a pupil direction measuring device section that measures the directions of the left and right pupils as seen from the display screen, and a convergence angle calculating device section that calculates the angle between the pupils of the left eye and the pupils of the right eye as seen from the display screen from the measured pupil directions, The device for preventing vision loss described in claim 1, characterized in that the specified condition is that the calculated convergence angle is determined to be equal to or greater than a pre-stored alert convergence angle for a specified period of time or more.

4. the convergence state is a convergence angle of the user's eyes, The convergence state measuring device comprises a screen distance measuring device unit that measures a screen distance between the display screen and the user's eyes, and a convergence angle calculating unit that calculates a convergence angle from the interpupillary distance between the user's left and right eyes and the screen distance measured by the screen distance measuring device unit, 2. The device for preventing eyesight deterioration according to claim 1, wherein the predetermined condition is that the calculated convergence angle is determined to be equal to or greater than a pre-stored alert convergence angle.

5. the convergence state is a convergence angle of the user's eyes, The convergence state measuring device comprises a screen distance measuring device unit that measures a screen distance between the display screen and the user's eyes, and a convergence angle calculating unit that calculates a convergence angle from the interpupillary distance between the user's left and right eyes and the screen distance measured by the screen distance measuring device unit, The device for preventing vision loss described in claim 1, characterized in that the specified condition is that the calculated convergence angle is determined to be equal to or greater than a pre-stored alert convergence angle for a specified period of time or more.

6. The device for preventing vision deterioration according to claim 4 or 5, characterized in that the alert convergence angle is calculated from a reference convergence angle calculated by the convergence angle calculation unit using a preset screen distance and the interpupillary distance of the user at that screen distance by an alert convergence angle determination unit provided in the convergence state measurement device.

7. 6. The device for preventing eyesight deterioration according to claim 4, wherein the interpupillary distance is calculated by an image processing unit through image processing of the image captured by the front camera.

8. 6. The device for preventing eyesight deterioration according to claim 1, further comprising a storage unit for storing the time (VDT time) that the user views the display screen.

9. the convergence state is a screen distance between the display screen and the user's eyes, The congestion state measuring device comprises a screen distance measuring device unit that measures the screen distance, 2. The device for preventing eyesight deterioration according to claim 1, wherein the predetermined condition is that the measured image distance is determined to be equal to or less than a pre-stored alert screen distance.

10. the convergence state is a screen distance between the display screen and the user's eyes, The congestion state measuring device comprises a screen distance measuring device unit that measures the screen distance, The device for preventing vision loss described in claim 1, characterized in that the specified condition is when the measured image distance is determined to be less than or equal to a pre-stored alert screen distance for a specified period of time or more.

11. the convergence state is the interpupillary distance between the left and right eyes of the user, the convergence state measuring device comprises an interpupillary distance measuring device for measuring the interpupillary distance of the user, 2. The device for preventing eyesight deterioration according to claim 1, wherein the predetermined condition is that the measured interpupillary distance is determined to be equal to or smaller than a pre-stored interpupillary distance.

12. the convergence state is the interpupillary distance between the left and right eyes of the user, the convergence state measuring device comprises an interpupillary distance measuring device for measuring the interpupillary distance of the user, 2. The device for preventing vision loss according to claim 1, wherein the predetermined condition is that the measured interpupillary distance is determined to be equal to or less than a pre-stored interpupillary distance for a predetermined period of time or more.

13. measuring a state of eye convergence of a user looking at a display screen of a display device having a front camera provided on a side where the display screen is located, by a convergence state measuring device provided on the display device; A method for preventing vision loss, characterized in that an instruction judgment unit provided in the display device compares the measured congestion state with a pre-stored alert congestion state, and if it determines that a predetermined condition is met, an alert is issued to an alert unit of the display device.

Images