A method for capturing images using a screen and an under-display camera.

Abstract

This invention discloses a screen and an under-display camera imaging method. The screen is an organic light-emitting diode (OLED) screen comprising a substrate layer, a light-emitting layer, and an anti-reflection layer. The light-emitting layer is disposed above the substrate layer and emits light. The anti-reflection layer is disposed above the light-emitting layer and receives the light emitted by the light-emitting layer, serving to eliminate reflection caused by incident light. The light incident on the anti-reflection layer includes at least ambient light outside the screen. By setting an anti-reflection layer on the light-emitting layer, and with a reasonable thickness and refractive index design, the reflected light from the incident light interferes with and cancels out, effectively solving the technical problems of low light transmittance and poor imaging effect when the camera module is placed under the screen, and high light transmittance leading to poor display effect due to screen reflection. This improves product quality and user experience.

Description

Technical Field

[0001] This invention relates to the field of under-display camera technology, and more specifically to a screen and an under-display camera method. Background Technology

[0002] The trend towards full-screen displays involves placing the front-facing camera under the screen. The camera's pixel display is disabled when in use and normal when not in use. Currently, most front-facing cameras on the market use OLED screens with self-emissive properties. While these screens have some light transmittance, it is relatively low. Under-screen front-facing cameras require high image quality for photography. During photo taking, the front-facing camera mostly passively receives ambient light. Given the small size and weak light sensitivity of the front-facing camera itself, low light transmittance leads to poor image quality, while high light transmittance results in poor display quality due to screen reflection. These are major problems with under-screen front-facing cameras. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the above-mentioned technical problems.

[0004] To address these issues, embodiments of the present invention propose a screen to solve the technical problems of poor imaging effect due to low light transmittance and poor display effect due to screen reflection caused by high light transmittance when the camera module is placed below the screen for recording.

[0005] The embodiments of the present invention also propose an under-display camera shooting method to solve the technical problems of low light transmittance and poor imaging effect when the camera module is placed under the screen for shooting, and poor display effect caused by screen reflection due to high light transmittance.

[0006] Embodiments of the present invention also propose a terminal to solve the technical problems of low light transmittance and poor imaging effect when the camera module in the terminal is placed below the screen for shooting, and poor display effect caused by screen reflection due to high light transmittance.

[0007] The embodiment of the present invention is an organic light-emitting diode (OLED) screen, comprising:

[0008] Substrate layer;

[0009] A light-emitting layer, wherein the light-emitting layer is disposed above the substrate layer and emits light; and

[0010] An anti-reflection layer is disposed above the light-emitting layer and receives the light emitted by the light-emitting layer, which is used to eliminate the reflection phenomenon caused by the incident light; wherein the light incident on the anti-reflection layer includes at least the ambient light outside the screen.

[0011] In some embodiments, the thickness of the antireflection layer is an odd multiple of a quarter wavelength of the incident light, and the refractive index of the antireflection layer is:

[0012]

[0013] Where n0 and n2 are the refractive indices of the media on both sides in the thickness direction of the antireflection layer, respectively.

[0014] In some embodiments, the light-emitting layer includes a plurality of organic light-emitting regions, which are respectively located above the substrate layer and arranged side by side along the length of the screen.

[0015] In some embodiments, the light-emitting layer includes an encapsulation layer disposed above the substrate layer; and the thickness of the organic light-emitting region is less than the thickness of the encapsulation layer, and the organic light-emitting region is located at the bottom of the encapsulation layer.

[0016] In some embodiments, there are multiple antireflective layers, the same number as the number of organic light-emitting regions; and in the thickness direction of the screen, one antireflective layer corresponds to one organic light-emitting region below it.

[0017] In some embodiments, the screen further includes a protective layer disposed on the light-emitting layer; and the thickness of the anti-reflection layer is less than the thickness of the protective layer, and the anti-reflection layer is located at the bottom of the protective layer.

[0018] In some embodiments, the plurality of organic light-emitting regions include a first light-emitting region emitting red light, a second light-emitting region emitting green light, and a third light-emitting region emitting blue light; the anti-reflection layer corresponding to the first light-emitting region, the second light-emitting region, and the third light-emitting region in the thickness direction of the screen is a first anti-reflection layer that receives incident red light, a second anti-reflection layer that receives incident green light, and a third anti-reflection layer that receives incident blue light.

[0019] In some embodiments, the substrate layer includes an OLED substrate and a light-transmitting metal thin-film transistor; the light-transmitting metal thin-film transistor is disposed above the OLED substrate; and the light-emitting layer is disposed above the light-transmitting metal thin-film transistor.

[0020] The under-display camera imaging method of this invention uses the screen described in any of the above embodiments of this invention, and the imaging method includes the following steps:

[0021] Remove the circular polarizer covering the top of the screen;

[0022] The camera is positioned below the screen; the pixel display is turned off when the camera is taking a picture, and normally displayed otherwise.

[0023] The terminal in this embodiment of the invention includes the screen described in any of the above embodiments of the invention.

[0024] According to the embodiments of the present invention, by setting an anti-reflection layer on the light-emitting layer, and by designing the appropriate thickness and refractive index of the anti-reflection layer, the interference of reflected light is mutually canceled. This not only increases the light transmittance of the screen to meet the high light transmittance requirements of the under-display camera, but also has an anti-reflection function to ensure the screen display effect, thereby improving product quality and user satisfaction. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of an under-display camera in related technologies;

[0026] Figure 2 This is a schematic diagram of the screen structure according to an embodiment of the present invention;

[0027] Figure 3 This is a flowchart illustrating the under-display camera's imaging process according to an embodiment of the present invention.

[0028] Figure label:

[0029] 1. Screen; 2. Light-emitting layer; 3. Color filter layer; 4. Light-blocking layer;

[0030] Screen 100;

[0031] Substrate layer 10; OLED substrate 101; Transparent metal thin-film transistor 102;

[0032] Light-emitting layer 20; encapsulation layer 201; first light-emitting area 202; second light-emitting area 203; third light-emitting area 204;

[0033] Anti-reflective layer 30; First anti-reflective layer 301; Second anti-reflective layer 302; Third anti-reflective layer 303;

[0034] Protective layer 40. Detailed Implementation

[0035] This invention is based on the inventor's discoveries and understanding of the following facts and problems:

[0036] The following is for reference. Figure 1 The description of the structure of screen 1 in the under-display camera of the related technology is as follows: screen 1 is an organic light-emitting diode (OLED) screen 1, wherein the OLED screen 1 uses an organic polymer material as the light-emitting layer 2, which can achieve self-illumination. Due to its special structure, the OLED screen 1 has a certain degree of light transmittance. Therefore, as... Figure 1 As shown, this feature can be utilized to achieve under-display camera recording by placing a camera below the OLED screen 1.

[0037] The OLED screen 1 includes a semi-transparent common cathode, partially transparent metal thin-film transistor (TFT) traces, a reflective metal anode, and an opaque yet luminescent layer 2. (See attached image.) Figure 1 The light-emitting layer 2 in the OLED screen 1 shown has a low light energy utilization rate for camera photography because the overall light transmittance of the OLED screen 1 is limited, reaching only 3% to 10%.

[0038] A conventional optimization approach is to reduce the pixel density of screen 1 to improve its light transmittance. Specifically, the pixel density is reduced only in the area of ​​screen 1 corresponding to the camera, while other areas of screen 1 maintain normal pixel density. However, since the same screen 1 has different pixel densities, users can clearly observe the difference in display quality, and this method achieves limited improvement.

[0039] In addition, conventional optimization solutions also mention that when placing a camera below the OLED screen 1, the circular polarizer placed above the OLED screen 1 can be removed to improve light transmittance. See [link to relevant documentation]. Figure 1 As shown, the camera is positioned below the OLED screen 1. Removing the circular polarizer positioned above the OLED screen 1 increases light transmittance, but ambient light is reflected back through the semi-transparent common cathode of the OLED screen 1, affecting the display effect. The downward arrows represent ambient light, and the upward arrows represent reflected light. To solve the reflected light problem, a color filter layer 3 can be added to the light-emitting layer 2 of the OLED screen 1. Multiple color filter layers 3 are arranged side-by-side along the length of the screen 1, and a light-shielding layer 4 is placed between two color filter layers 3 along the length of the screen 1. The color filter layer 3 is used to reduce reflected light, but this color filter layer 3 still results in some loss of light transmittance.

[0040] It should be noted that, taking the example of screen 1 where the length and left-right directions are consistent, the relevant technical solutions are described, where the vertical and horizontal directions are as follows: Figure 1 As shown.

[0041] Therefore, how to provide a shooting method for screen 1 and under-screen camera to solve the technical defects of low light transmittance and poor shooting effect when the camera module is placed under screen 1 and shooting, and the technical defects of poor display effect caused by screen reflection due to high light transmittance, is a technical problem that urgently needs to be solved by those skilled in the art.

[0042] Examples of the invention are described in detail below, with examples illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The examples described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0043] like Figure 2As shown, an embodiment of the present invention provides an organic light-emitting diode (OLED) screen 100, including a substrate layer, a light-emitting layer 20, and an anti-reflection layer 30. The light-emitting layer 20 is disposed above the substrate layer and emits light, and the anti-reflection layer 30 is disposed above the light-emitting layer 20 and receives the light emitted by the light-emitting layer. It is used to eliminate the reflection phenomenon caused by incident light; wherein the light incident on the anti-reflection layer includes at least ambient light outside the screen.

[0044] It should be noted that the antireflection layer has the effect of reducing or eliminating reflection of all incident light. In this embodiment, the light incident on the antireflection layer includes ambient light outside the screen as well as light emitted by the light-emitting layer. The antireflection layer has the effect of reducing reflection of incident ambient light to prevent glare. It also has the effect of eliminating reflection of incident light emitted by the light-emitting layer, increasing the transmittance of light emitted by the light-emitting layer to achieve better under-display camera imaging effect.

[0045] The thickness of the antireflection layer 30 is an odd multiple of a quarter wavelength of the incident light, and the refractive index of the antireflection layer 30 is:

[0046] Where n0 and n2 are the refractive indices of the media on both sides of the antireflection layer 30 along its thickness direction.

[0047] As will be understood by those skilled in the art, the antireflection layer 30 is a film structure with a certain thickness. The antireflection layer 30 has an upper surface and a lower surface that are relatively positioned opposite each other in the thickness direction. Taking incident light entering from above onto the upper surface of the antireflection layer 30 as an example: according to the principle of light incidence, the incident light undergoes reflection and refraction at the upper surface of the antireflection layer 30. The reflected light is the first layer of reflected light. The refracted light, based on the refractive index of the antireflection layer 30, can propagate in a straight line within the antireflection layer 30 and enter the lower surface of the antireflection layer 30, where it undergoes reflection and refraction. The refracted light then exits through the lower surface of the antireflection layer 30, while the reflected light is the second layer of reflected light. By setting the thickness and refractive index of the antireflection layer 30, when the peak of the first layer of reflected light corresponds to the trough of the second layer of reflected light, and the trough of the first layer of reflected light corresponds to the peak of the second layer of reflected light, the first and second layers of reflected light interfere with and cancel each other out.

[0048] To make the technical solution of this application easier to understand, the following description uses the example where the thickness direction of screen 100 is consistent with the vertical direction, the length direction of screen 100 is consistent with the horizontal direction, and the thickness direction of anti-reflective layer 30 is the same as the thickness direction of screen 100. The vertical and horizontal directions are as follows... Figure 2 As shown.

[0049] The light-emitting layer 20 is disposed above the substrate layer, and the anti-reflection layer 30 is disposed above the light-emitting layer 20. In other words, the light-emitting layer 20 has an upper surface and a lower surface that are opposite each other in the vertical direction, the substrate layer is disposed below the lower surface of the light-emitting layer 20, and the anti-reflection layer 30 is disposed above the upper surface of the light-emitting layer 20.

[0050] Those skilled in the art will understand that the substrate layer is a semi-transparent material that allows some light to pass through, while the organic light-emitting area in the light-emitting layer 20 is opaque but can emit light. Specifically, the light-emitting layer 20 includes multiple organic light-emitting areas, which emit light containing three colors of RGB (red, green, and blue) and are arranged side by side in the left-right direction above the substrate layer. For example, the multiple organic light-emitting areas are a first light-emitting area 202 that emits red light, a second light-emitting area 203 that emits green light, and a third light-emitting area 204 that emits blue light.

[0051] Optionally, the antireflection layer 30 is an AR antireflection film. Since the wavelengths of light incident on the antireflection layer 30 are different, antireflection films of different thicknesses can be used. Therefore, the number of antireflection layers 30 is the same as the number of organic light-emitting regions. For example, multiple antireflection films can be configured as follows: a first antireflection layer 301 receiving red light, a second antireflection layer 302 receiving green light, and a third antireflection layer 303 receiving blue light, corresponding vertically to the first light-emitting region 202, the second light-emitting region 203, and the third light-emitting region 204. In the vertical direction, one antireflection layer 30 corresponds to one organic light-emitting region below it, ensuring that light emitted from the organic light-emitting region enters the corresponding antireflection layer 30. This not only achieves the antireflection effect of the light emitted from the light-emitting layer 20 but also specifically improves the RGB transmittance of the corresponding pixel.

[0052] To achieve the anti-reflective effect, for example, such as Figure 2 As shown, the thickness of the first antireflective layer 301 is:

[0053]

[0054] Where h1 is the thickness of the first antireflection layer 301, k is an odd value, and λ1 is the wavelength of red light;

[0055] The wavelength of red light is known to be 620-750nm. To achieve the anti-reflection effect of the first anti-reflection layer 301, h1 = k * (155-188)nm, that is, the minimum thickness of the first anti-reflection layer 301 is h1 = k * 155nm, and its maximum thickness is h1 = k * 188nm; similarly, the thicknesses of the second anti-reflection layer 302 and the third anti-reflection layer 303 can be calculated.

[0056] The refractive index of the first antireflective layer 301 is:

[0057]

[0058] Where n0 and n2 are the refractive indices of the media on the upper and lower sides of the first antireflection layer 301, respectively;

[0059] It is known that the refractive index of the medium on both sides of the first antireflection layer 301 is a constant. Optionally, the medium on both sides of the first antireflection layer 301, the second antireflection layer 302, and the third antireflection layer 303 are the same, so the refractive index of the first antireflection layer 301, the second antireflection layer 302, and the third antireflection layer 303 is the same.

[0060] In this embodiment, an anti-reflection layer 30 is provided on the light-emitting layer 20. The anti-reflection layer 30 is designed with a reasonable thickness and refractive index to specifically improve the RGB transmittance of the corresponding pixel points, so that the interference of reflected light cancels each other out. This not only increases the transmittance of the screen 100 to meet the high transmittance requirements of the under-display camera, but also has an anti-reflection function to ensure the display effect of the screen 100.

[0061] In some embodiments, the light-emitting layer 20 includes an encapsulation layer 201 disposed above the substrate layer; and the thickness of the organic light-emitting region is less than the thickness of the encapsulation layer 201, with the organic light-emitting region located at the bottom of the encapsulation layer 201.

[0062] Specific examples Figure 2 As shown, the encapsulation layer 201 is disposed above the substrate layer, and the thickness of the organic light-emitting region is less than the thickness of the encapsulation layer 201 and is located at the bottom of the encapsulation layer 201. In other words, the thicknesses of the first light-emitting region 202, the second light-emitting region 203, and the third light-emitting region 204 are all less than the thickness of the encapsulation layer 201. They are all disposed at the bottom of the encapsulation layer 201 and above the substrate layer, and the first light-emitting region 202, the second light-emitting region 203, and the third light-emitting region 204 are arranged side by side along the left-right direction at the bottom of the encapsulation layer 201. Furthermore, the encapsulation layer 201 is located between the first light-emitting region 202 and the second light-emitting region 203, and between the second light-emitting region 203 and the third light-emitting region 204 in the left-right direction.

[0063] Optionally, the encapsulation layer 201 is a multilayer film structure, specifically thin-film encapsulation (TFE). TFE encapsulation is generally a 3-layer film structure, which protects the organic light-emitting area.

[0064] In some embodiments, the screen 100 further includes a protective layer 40 disposed above the light-emitting layer 20; and the thickness of the anti-reflection layer 30 is less than the thickness of the protective layer 40, and the anti-reflection layer 30 is located at the bottom of the protective layer 40.

[0065] Specific examples Figure 2As shown, the protective layer 40 is disposed above the encapsulation layer 201, and the thickness of the antireflective layer 30 is less than the thickness of the protective layer 40. Multiple antireflective layers 30 are arranged side-by-side along the bottom of the protective layer 40 in a left-right direction. In other words, the thicknesses of the first antireflective layer 301, the second antireflective layer 302, and the third antireflective layer 303 are all less than the thickness of the protective layer 40. They are all disposed at the bottom of the protective layer 40 and above the encapsulation layer 201, and are arranged side-by-side along the bottom of the protective layer 40 in a left-right direction.

[0066] Optionally, a protective layer 40 is provided between the first antireflective layer 301 and the second antireflective layer 302 in the left-right direction, and between the second antireflective layer 302 and the third antireflective layer 303. In this embodiment, the protective layer 40 protects the antireflective layer 30.

[0067] In some embodiments, the substrate layer includes an OLED substrate 101 and a light-transmitting metal thin-film transistor 102; the light-transmitting metal thin-film transistor 102 is disposed above the OLED substrate 101; and the light-emitting layer 20 is disposed above the light-transmitting metal thin-film transistor 102.

[0068] Specific examples Figure 2 As shown, a light-transmitting metal thin-film transistor 102 is disposed above the OLED substrate 101; multiple organic light-emitting regions and an encapsulation layer 201 are located above the light-transmitting metal thin-film transistor 102. The OLED substrate 101 supports each structure, and the light-transmitting metal thin-film transistor 102 consists of TFT traces, which is a type of active-matrix liquid crystal display. It can "actively" control each individual pixel on the screen 100, which can greatly improve the response time and provide a wide viewing angle.

[0069] The under-display camera shooting method of this embodiment includes the following steps:

[0070] Remove the circular polarizer covering the top of screen 100;

[0071] Position the camera below the screen (100 pixels); turn off pixel display when the camera is taking a picture, and otherwise display pixels normally.

[0072] Specific examples Figure 3As shown, the steps of the under-display camera imaging method proposed in this embodiment of the invention are as follows: removing the circular polarizer covering the top of the screen 100, thereby greatly improving the light transmittance of the screen 100, solving the technical problem of low light transmittance and poor imaging effect of the camera, and at the same time, the setting of the anti-reflection film can avoid the technical problem of poor display effect of the screen 100 caused by ambient light reflection. In addition, it is not necessary to reduce the pixel density on the screen 1 corresponding to the camera, avoiding the technical problem of poor display effect caused by the inconsistency of pixels between the screen 100 corresponding to the front camera and the surrounding screen 100.

[0073] The terminal in this embodiment of the invention includes the screen 100 in any of the above embodiments of the invention.

[0074] According to the imaging method of the under-display camera of the screen 100 of the present invention, by setting an anti-reflection layer 30 on the light-emitting layer 20, the reasonable thickness and refractive index design of the anti-reflection layer 30 makes the interference of reflected light cancel each other out, thus meeting the high light transmittance requirements of the under-display camera and preventing ambient light reflection, ensuring the display effect of the screen 100, and improving product quality and user satisfaction.

[0075] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0076] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0077] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0078] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0079] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "embodiment," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0080] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A screen, characterized in that, The screen is an organic light-emitting diode (OLED) screen, comprising: Substrate layer; A light-emitting layer, wherein the light-emitting layer is disposed above the substrate layer and emits light; and An anti-reflection layer is disposed above the light-emitting layer and receives the light emitted by the light-emitting layer, which is used to eliminate the reflection phenomenon caused by incident light; wherein the light incident on the anti-reflection layer includes at least the ambient light outside the screen; The thickness of the antireflection layer is an odd multiple of a quarter wavelength of the incident light, and the refractive index of the antireflection layer is: Where n0 and n2 are the refractive indices of the media on both sides in the thickness direction of the antireflection layer, respectively.

2. The screen according to claim 1, characterized in that, The light-emitting layer includes multiple organic light-emitting regions, which are located above the substrate layer and arranged side by side along the length of the screen.

3. The screen according to claim 2, characterized in that, The light-emitting layer includes an encapsulation layer disposed above the substrate layer; and the thickness of the organic light-emitting region is less than the thickness of the encapsulation layer, and the organic light-emitting region is located at the bottom of the encapsulation layer.

4. The screen according to claim 2 or 3, characterized in that, There are multiple antireflective layers, the same number as the number of organic light-emitting regions; and in the thickness direction of the screen, one antireflective layer corresponds to one organic light-emitting region below it.

5. The screen according to claim 2 or 3, characterized in that, It also includes a protective layer disposed above the light-emitting layer; and the thickness of the anti-reflection layer is less than the thickness of the protective layer, and the anti-reflection layer is located at the bottom of the protective layer.

6. The screen according to claim 4, characterized in that, The plurality of organic light-emitting regions include a first light-emitting region emitting red light, a second light-emitting region emitting green light, and a third light-emitting region emitting blue light; the anti-reflection layer corresponding to the first light-emitting region, the second light-emitting region, and the third light-emitting region in the thickness direction of the screen is a first anti-reflection layer that receives incident red light, a second anti-reflection layer that receives incident green light, and a third anti-reflection layer that receives incident blue light.

7. The screen according to any one of claims 1-3, characterized in that, The substrate layer includes an OLED substrate and a light-transmitting metal thin-film transistor; the light-transmitting metal thin-film transistor is disposed above the OLED substrate; the light-emitting layer is disposed above the light-transmitting metal thin-film transistor.

8. A method for capturing images using an under-display camera, characterized in that, Using the screen described in any one of claims 1-7, the camera's imaging method includes the following steps: Remove the circular polarizer covering the top of the screen; The camera is positioned below the screen; the pixel display is turned off when the camera is taking a picture, and normally displayed otherwise.

9. A terminal, characterized in that, Includes the screen as described in any one of claims 1-7.

Images