BR102012010884B1 - CONFIGURABLE DISPLAY DEVICES TO COMPENSATE VISUAL ABERRATIONS - Google Patents

Abstract

configurable display devices to compensate for visual aberrations the invention contemplates the use of means to reflect, refract or emit light and of means to control the direction in which light is emitted, refracted or reflected, which are configured to display images that compensate for visual deficiencies of Its users. In this sense, the use of two panels stands out, one for emission or reflection of light, and the other for controlling the direction of light emission. The joint configuration of these two panels allows the user to compensate for visual impairments. the technology can be used by LCD panel manufacturers and applied to television screens, computer video monitors, notebooks, netbooks, tablets, digital watches, calculators, electronic game consoles, e-readers, cell phones and telephones wireless and digital displays of electronic devices in general.

Description

The invention of the configurable display device to compensate for visual aberrations is directly applied to any type of electronic device that has a digital screen. Examples of these types of electronic devices include, but are not limited to, video monitors, televisions, clocks, alarm clocks, automobile dashboards, fitness center equipment, cell phones, calculators, blood pressure monitors, tablets, digital devices, electronic game consoles, e-readers, etc.

This technology can be used by manufacturers of LCD panels, televisions, computer monitors, and any products that use a digital screen. Manufacturers of this type of products have a special interest in using the present invention, as they can make the technology available directly on their 3D LCD panels. Any manufacturer of TVs, video monitors, cell phones, tablets, and other digital tools are also potential candidates to include this technology in their products.

The invention solves the problem of displaying content (texts, data, images, graphics, etc.) for people with vision problems that imply reduced visual acuity. The invention allows these people to interpret such contents without the need to use prostheses (glasses, contact lenses) or surgery. The new display uses a system of light fields (individually directed beams of light) to produce a correction that improves the visual acuity of its users. The light-field displays (known as light-field displays) are known in the academic community and have already been described in the literature. Light field displays are devices that have the ability to display an image using means to reflect or emit light and means to control the direction in which light is emitted or reflected. In light field displays, the means for reflecting, refracting, or emitting light are comprised of a back panel of pixels that emit or refract light, and the means for controlling the direction in which light is emitted, refracted, or reflected are formed by a front panel (which can be configured to go from opaque to fully transparent to light) or by an array of micro lenses. This is, however, the first time that light field screens have been used for the purpose of improving the visual acuity of individuals. Visual acuity is significantly increased when the screen is viewed by the visually impaired person for which the screen is configured to correct. The invention supports conditions such as myopia, hyperopia, astigmatism and presbyopia, in addition to higher order aberrations and cataracts, and combinations thereof. The screens are configurable to the conditions of each individual, and the same screen can be used by several users at different times or at the same time. The screens are programmable through software, and adapt to the conditions of different users by providing parameters that describe the characteristics of each user. Note that software programming is done on any state-of-the-art screen, where the software controls the screen content that can be dynamically changed through frame-by-frame display. In the case of the invention, the software modifies the displayed content to compensate for a specific user's visual impairment.

The problem that the invention solves was solved before, with the use of glasses, contact lenses, or surgeries. In the academic literature it is possible to find contact lenses with adaptive optics and other types of optical materials that somehow correct vision. However, there is no device/screen/monitor record capable of adapting to the visual aberrations present in an individual's eyes.

Previously available solutions to the problem that the invention solves were not fully satisfactory for the following reasons. The use of glasses is undesirable in some situations, such as the use of head-mounted devices (eg, portable monitors used in virtual reality and augmented reality applications, which are commonly called head-mounted displays'), during practice. of sports, etc. Also consider as an example the case of a person who uses reading glasses only. This person needs to wear the glasses each time they use their cell phone or check their watch. The invention, applied to these devices, makes it possible to use them without glasses. In this case, the glasses could only be used in situations of longer use, avoiding the inconvenience of systematically putting them on and taking them off.

The invention solves the problem as follows. The new screen uses a system of light fields, which can be obtained, for example, by composing two panels of pixels (which can be LCD, AMOLED, or other technology) positioned at a certain distance, one in front of the other. . Alternatively, the invention may be practiced through a panel of pixels with an array of micro-lenses positioned in front of the panel. In this case, the means for reflecting or emitting light are composed of a panel that emits light and the means for controlling the direction in which the light is emitted or reflected are formed by an array of micro-lenses positioned in front of the panel. A third variant of the solution would use a panel of nano components that direct light (nano antennas).

The inventive approach creates a kind of hologram that adjusts to the viewer's visual conditions. The screen compensates for refractive errors (eg, myopia, hyperopia, presbyopia, astigmatism, and high-order aberrations) and prevents light scattering in paths that reach a cataract. The objective is to free the user from the need to use corrective lenses when he looks at the digital screen, and/or to postpone the need for eye surgery. Note that the same technique can be applied to static prints on a support material, including plastic, paper, fabric, wood, among others. Thus, the proposed way of solving the problem differs from the previously available solutions. The feature of the invention that makes it different from previously available solutions is the adaptation of the device in order to compensate for the user's vision problem. Thus, the device presents the user with an image that appears distorted (1), as shown in Figure 1, to an individual with no visual impairment, but is perceived without distortion (2) by the user for whom the image was created (with the to compensate for their visual impairment).

The invention will be better understood with the aid of the following figures.

Figure 1 illustrates the perceptions of an individual with reduced visual acuity (2.5 degrees of hyperopia) when looking at a conventional screen (monitor) image (1) and when looking at a compensated (distorted) image for their specific visual condition, displayed on a screen object of the present invention (2).

Figure 2 describes the principle used by the present invention to form an image in focus on the retina of an individual that presents variations in its refractive power at different points/optical paths in the eye. This figure features a configuration formed by two LCD panels: the back panel (3) and the front panel (4), separated by a distance m (note that light field screens already exist prior to this invention). Light emitted by six pixels (represented by circles) located on the back panel passes through a set of lit pixels on the front panel. This defines a set of rays that strike the observer's cornea (5). Rays originating from the three pixels at the top of the back panel converge at point k1 on the cornea. In turn, rays originating from the three pixels at the bottom of the back panel converge at point k2 on the cornea. These rays are refracted by the cornea and pass through the aperture of the pupil (p), pass through the lens (6), and then strike the observer's retina (7). Distance a represents the axial length of the eye, measured from the cornea to the retina, while t represents the distance between the cornea and the front panel. Enumerating the pixels on the back panel, from top to bottom, it can be seen that the rays from the first and fourth pixels converge to the same point on the retina, following paths that pass through k1 and k2, respectively. Similarly, rays from the second and fifth pixels converge to another point on the retina. The same situation occurs for rays coming from the third and sixth pixels. Points k1 and k2 have different focal lengths (which constitute an optical aberration), represented by fk1 and fk2, respectively. The distance jk1 is the distance at which all points on a plane seen through k1 appear in focus on the retina. Such a plane is indicated by Ik1. Similarly, Ik2 represents the plane conjugated to the retina with respect to the optical power of point k2. S1 is the distance between the lowest (sixth) pixel in the back panel and the horizontal (imaginary) line passing through the center of the pupil. S2 is the distance from the opening on the front panel through which the light from the sixth pixel from the rear panel passes with respect to the same horizontal line. From the explanations above, it can be seen that from the knowledge of the optical power associated with the different paths between the cornea and the retina, and from the specification of an image to be projected on the retina, it is possible to define a combination of pixels that must be lit on the back panel and which must be made translucent on the front panel in order to obtain the desired effect.

Figure 3 describes how a ray of light that leaves the front panel (8) at an angle of α (alpha) degrees with respect to the horizontal and at a distance S2 from the horizontal line, which passes through the center of the pupil, reaches the cornea assembly. -crystalline (9) at a distance k from the center of the pupil. At this point, the optical power of the observer's eye has a focal length of f(k). This ray is then refracted and strikes the observer's retina (10) at a distance R from the horizontal line passing through the center of the pupil. The distance from the front panel to the cornea-lens assembly is represented by t, while a is the axial length of the eye (distance from the cornea to the retina).

Figure 4 shows the contents of the front and rear panels for the projection of a letter G (uppercase) with an approximate size of 0.9 mm on the retina of an observer with 5 degrees of myopia. The small, sparsely distributed light dots (11) represent the small openings on the front panel, while the mid-tone regions (12) represent the content displayed on the back panel.

Figure 5 shows the result of the simulation of the same letter G presented in Figure 4, this time considering that the observer has 5 degrees of myopia and one caratar. This illustration considers the case of the invention using a single panel with a lenticular matrix (micro-lens matrix). The bright regions (13) represent the content displayed on the panel, while the small circles (14) indicate unused regions to prevent the corresponding rays from reaching a cataract.

The approach of the invention can be described as the projection of anisotropic patterns at different depths according to spatially distributed aberrations in the eye of the observer. These optical aberrations are represented as focal lengths on an aberration map. Projected patterns are anisotropic images placed at the right point in focus for a given optical power of the aberration map. Figure 2 shows two image planes (I_k1 and I_k2), each for a specific point on the cornea (k1 and k2). Since the optical power of point k1 is greater than the optical power of point k2, the plane I_k2 should be placed farther from the eye than the plane I_k1 and magnified accordingly. Note how individual light rays from respective objects in each image plane are integrated into the retina, as shown in Figure 2, (7).

As these images are placed at multiple depths to create a single image in focus on the retina, we say that the system is multi-depth. The method divides the field of light coming from an object into several parts and positions them at different depths, making sure that these are only seen through the region of the eye that has a certain optical aberration. Light paths that pass through opacities, such as cataracts, are avoided. The end result is a field of light to be displayed at a given distance from the eye.

The invention eliminates the need to wear glasses, contact lenses, and/or perform refractive surgery.

The light field screens described above allow you to create images that respect the limits of the user's focal length range, and that are configured specifically for the user's characteristics. This eliminates the need to use contact lenses or glasses to see the content displayed on the screen more clearly.

The innovative features of the invention stem from the possibility of controlling the direction of the rays that leave each pixel on the monitor and reach the region of the user's eye delimited by its pupil. Considering that visual aberrations vary spatially on the surface of the eye, the present invention controls the direction of incident light at each pupil io point. Such directions are calculated so that light rays coming from various points on the monitor converge to form a sharp image on the user's retina (as illustrated in Figure 2). To do so, it is necessary to have a map that describes the optical power of each point on the surface of the eye in the region delimited by the pupil. Such a map is assumed as input to configure the present invention, and can be obtained using existing equipment and techniques. The present invention does not generate such maps.

The invention comprises a light field screen (which can be built, for example, using two LCD or AMOLED panels, or other technology) and software that controls both panels. The software 20 calculates, for each content intended to be projected onto the retina, which pixels on the back panel should be illuminated in combination with the pixels on the front panel that should be made translucent. In the case of using an array of micro-lenses, as these are fixed, the software calculates which pixels of the panel should be illuminated. As shown in Figure 2, the back panel (3) displays the various components of the contents to be displayed, while the front panel (4) controls the openings through which rays from the back panel (3) can proceed towards to the user's eye. Thus, the combination of the illuminated positions on the back panel (3) and the unblocked positions on the front panel (4) controls the directions of the rays that reach the different points in the observer's pupil, allowing the formation of a sharp image on his retina. . The entire configuration process of the two panels is controlled by the software, which uses as a parameter for configuration the map that describes the optical power of each point in the region delimited by the observer's pupil.

In case the invention is practiced using a panel with an array of micro-lenses, the software determines which pixels of the panel should be lit to project the desired image onto the user's retina.

The use of equipment to track the position and orientation of the observer's eye allows him to observe dynamically updated contents from different points of view, creating an effect similar to that of observing a hologram.

In Figure 2, the two panels (back (3) and front (4)) are LCD modules (or AMOLED, or other technology) that can be purchased independently in specialized stores. Together (and positioned at a distance from each other), they allow the projection of light rays in a set of directions, while each pixel on a conventional monitor emits light with almost equal intensity in all directions. This ability to project rays of light in specific directions is used to project images created specifically for their visual condition into the user's eye. By tracking the position of the user's eye, it is possible to dynamically update the contents displayed on the back panel (3) and the openings on the front panel (4), creating an effect similar to observing a hologram.

The software implements a two-step algorithm: (i) an association between light rays exiting the device at a given angle (S2, k) and retinal positions (R) (as shown in Figure 3); and (ii) a normalization in intensity between the rays that make up a single point on the retina. Taking as input: an expected retinal image (l_Retina), an aberration map, and a cataract map that characterizes the user's eye, the method produces a light field to be displayed on a light field screen.

Using geometric optics and the thin lens model, the relationship between a ray from a point S2 on the screen at an angle α and the point on the retina R is given by the following formula (where the elements are indicated in Figure 3):k = S2 + tan α tR(S2, k) = a (-k/f(k) + tan a) + k (Eq. 1), where f(k) is the focal length at position k at the eye opening, the variable t is the distance from the light field viewer to the eye, and the variable a is an axial length of the eye. f(k) is calculated from the aberration map or through interpolation of user prescription data. The variable a is essentially a scale factor, measured for the specific user (alternatively, you can use a=23.8 millimeters, which is the average value of an axial length of the human eye). The energy I that reaches the retina at a point x of R is the integral of the energy received by all points on the cornea visible through a pupil of diameter p and that reach x: IRetina (R) = \integral ILightfield [S2 (R, k), k] * h(k) dk, where the function S2(k,R) is obtained by solving the previous equation for S2. IRetina(R) is the intensity accumulated at point R on the retina. ILightfield(S2, k) is the intensity emitted by the light field through point k on the cornea from position S2 (indicated in Figure 3). h(k) is a binary visibility function for opacities (cataracts).

Using many rays of light to form each pixel on the retina (many-to-one mapping) increases brightness but requires a normalization step. The intensity of each ray of the light field is the retinal intensity divided by the number of incoming rays n(R) at each retinal position R:ILightfield(S2, k) = IRetina(R) / n(R) (Eq . two),

Cataract-affected areas are removed using the binary function h(k), which is based on the cataract density function c(k), given as input and measured with traditional ophthalmic equipment. A threshold H defines the cataract density at which the effects are no longer noticeable: h(k) = 1 if c(k) <H,h(k) = 0 if c(k) >= H,

Circles (14) indicated in Figure 5 highlight that light rays are being blocked because of the above function.

Given a screen configuration, aberration maps f(k), and cataract maps h(k), the method calculates the position R for each pair of rays and light (S2, k) by applying the equation (Eq. 1)

The accession numbers r(R) to each retinal point R are calculated and stored. Given the desired image on the retina, IRetina, we define ILightfield (S2, k) from the input image IRetina(R) and apply the second equation (Eq. 2) to normalize the intensity of each ray defined by (S2, k) . A light field display can be constructed using a dual stack of LCDs or with an LCD plus a lenticular matrix (micro-lens matrix). Figure 4 which describes the invention shows examples of the contents of the back panel (3) and the front panel (4) in the case of a monitor formed by two LCDs. Figure 5 shows the contents of the back panel [shown in Figure 2(3)], used with a lenticular array (microlens array).

It is understood that the invention can also be practiced statically, through printing on sheets of paper, plastic and others. However, printing on a single sheet of paper would not work, as the light would be reflected on the paper diffusely (in all directions). This would be equivalent to having a monitor with a single layer (single panel). For printing to work statically on paper it is necessary to use two layers of paper (or ink on paper), a layer behind (reflecting or emitting light) and another layer in front (this one controlling the directions in which the light from the back paper could escape). In this case the configuration of the invention would be similar to the use of two panels. However, two points must be highlighted. The first point is that the configuration would be static, i.e., it could not be dynamically modified over time to: update the displayed contents; or to adjust to changes in the position of the observer's head; or to accommodate observers with other disabilities, for example. The second point is that a problem of light efficiency may occur. This problem is related to the way light would hit the back panel (or layer of paint or paper) to be reflected. One possibility to increase the luminous efficiency would be to illuminate the back sheet from behind, causing the light to pass through the back panel and reach the holes in the front panel. This is the working principle of LCD monitors, which have a diffused lighting (light box) behind the LCD layer itself. The use of light field screens resolves the points discussed above. In other words: the use of two panels allows dynamic configuration combined with greater luminous efficiency.

Note that the correction is made for one eye, due to the peculiarities of the refractive conditions of each eye, and their different relative positions with respect to the panels. The invention also supports the display for two eyes from the same deformed image.

Alternatively, the invention can also be practiced by configuring the panels dynamically by a screen that multiplexes the contents between the two eyes. For example, if the system generates images at a rate of 60 frames per second, it could alternate the display of specific content for each of the eyes, which would each receive, alternately, 30 frames per second. This is an important aspect for the practice of the invention, since without contemplating this multiplexing of the correction configuration, the invention becomes monocular. Considering that the two eyes of the same person are in different positions and often require different optical corrections, the multiplexed display for the two eyes is an important aspect for the practice of the invention.

Prior to the invention proposed here, a method is introduced where a person can adjust a screen by means of software to change its configuration until the user deems it suitable for his visual impairment. But this anteriority does not mention means to control the direction of light. The display device is a traditional monitor and it is assumed that it is possible to correct the image without changing the direction of the light rays. The invention proposed here has as a first differential the control of the direction of light rays and this control is a requirement for the correction of a given image to be perfectly adequate to compensate for a person's visual deficiencies. The invention proposed here has as a second differential the specific consideration of data on the disability of the user for which the image will be corrected. In other words: the invention proposed here takes into account whether the person has myopia, hyperopia, cataract, etc., and makes the correction for the specific case. In addition, it can correct different specific cases for left and right eye by Simultaneous display of specific content for each eye [MMoijo or alternate display of frames suitable for each eye.

Another priority in relation to the invention proposed here is based on a handheld device, while the invention proposed here can be used in any display equipment, regardless of its size or material. According to the above mentioned, the modulation device alters a light wave in terms of phase and wavelength or causes diffraction. Note that the alteration of a light wave in terms of phase and wavelength or the diffraction of a ray of light does not change the direction of this ray of light. Again, the invention proposed here differs from this prior art. The invention proposed here has as a first differential the control of the direction of light rays and this control is a requirement for the correction of a given image to be perfectly adequate to compensate for a person's visual deficiencies. The invention proposed here has as a second differential the specific consideration of data on the disability of the user for which the image will be corrected. In other words: the invention proposed here takes into account whether the person has myopia, hyperopia, cataract, etc., and makes the correction for the specific case. In addition, it can correct different specific cases for the left and right eye by simultaneously displaying specific content for each eye |[MMO2]0U alternating display of frames suitable for each eye.

An example of the image alteration features by the invention proposed here can be seen in Figure 4. Figure 4 shows the contents of the front and rear panels for the projection of a letter G (uppercase) with an approximate size of 0.9 mm on the retina of a observer with 5 degrees of myopia. The small, sparsely distributed light dots (11) represent the small openings on the front panel, while the mid-tone regions (12) represent the content displayed on the back panel. Note that the combination of the two settings, both the front panel and the back panel, allows control of the direction of the light rays, as illustrated in Figure 2.

Another example of the image alteration characteristics by the invention proposed here can be seen in Figure 5. Figure 5 shows the result of the simulation of the same letter G presented in Figure 4, this time considering that the observer has 5 degrees of myopia and a face . This illustration considers the case of the invention using a single panel with a lenticular matrix (micro-lens matrix). The bright regions (13) represent the content displayed on the panel, while the small circles (14) indicate unused regions to prevent the corresponding rays from reaching a cataract. Note that the combination of the two configurations, both the panel and the micro-lens array, allows control of the direction of the light rays, as illustrated in figure 2.

The invention can be practiced in any device, programmable or not, which is capable of displaying an image using means for reflecting or emitting light and means for controlling the direction in which light is emitted or reflected.

Claims (14)

1. “DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS” having the ability to display images using means to reflect, portray or emit light and means to control the direction in which light is emitted, portrayed or reflected characterized by the means to reflect, portray or emit light and the means for controlling the direction in which light is emitted, portrayed or reflected be configured to display images in a way that compensates for a specific user's visual impairment. 2. “DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS” according to claim 1 characterized by the means for reflecting, refracting or emitting light and the means for controlling the direction in which the light is emitted or reflected being dynamically configured to compensate for the deficiency visual of a specific user. 3. "DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS" according to claim 2 characterized by the means to reflect, refract or emit light and the means to control the direction in which the light is emitted, portrayed or reflected being dynamically configured through software to compensate for a specific user's visual impairment. 4. “DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS” according to claim 3 characterized by the software using information about a specific user's visual impairment. 5. DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS" according to claim 4 characterized by the means for reflecting, portraying or emitting light and the means for controlling the direction in which the light is emitted, portrayed or reflected being dynamically configured to compensate for the visual impairments of the left eye and visual impairments of the right eye, simultaneously or alternately. 6. “DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS” according to claim 5 characterized by the means for reflecting, portraying or emitting light and the means for controlling the direction in which light is emitted, portrayed or reflected being dynamically configured to display images for each eye to compensate for the visual impairment of a specific user who has distinct impairments in their left and right eyes. 7. "DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERATIONS" according to claim 1 characterized in that the means for reflecting, portraying or emitting light are composed of one or more panels of pixels to control the direction in which the light from each pixel is emitted , reflected or portrayed electronically. 8. “CONFIGURABLE DISPLAY DEVICES TO COMPENSATE VISUAL ABERRATIONS” according to claim 1 characterized in that the means for reflecting, portraying or emitting light are composed of a back panel that emits or is transparent the light and the means to control the direction in which the light is emitted, portrayed or reflected are formed by a front panel that can be configured to become opaque or transparent to light, with intermediate scales. 9. "DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS" according to claim 1 characterized in that the means to reflect, refract or emit light are composed of a back panel that emits or is transparent the light and the means to control the direction in which light is emitted, refracted or reflected are formed by an array of micro-lenses positioned in front of the rear panel. 10. “DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS” according to claim 1 characterized by the means for reflecting, refracting or emitting light and the means for controlling the direction in which light is emitted, refracted or reflected being statically configured to compensate the visual impairment of a specific user. 11. "DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS" according to claim 10 characterized by the means for reflecting, refracting or emitting light and the means for controlling the direction in which the light is emitted, refracted or reflected being formed by transfer or recording images for one or more supporting materials. 12. "DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS" according to claim 10 characterized in that the means for reflecting, refracting or emitting light are formed by transferring or recording images to one or more support materials that emit, reflect, or transmit light and the means for controlling the direction in which light is emitted, portrayed or reflected are formed by an array of micro-lenses positioned in front of the means for reflecting, refracting or emitting light. 13. "DISPLAY DEVICES CONFIGURABLE TO COMPENSATE VISUAL ABERRATIONS" according to claim 11 or 12 5 characterized in that the support material is paper, plastic, fabric, wood or acetate. 14. "CONFIGURABLE DISPLAY DEVICES TO COMPENSATE VISUAL ABERRATIONS" according to claim 1 characterized in that the means to reflect, refract or emit light are composed of an io panel of nano components to control the direction in which the light from each pixel is emitted , reflected or portrayed electronically.

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