WO2023051476A1

WO2023051476A1 - Filtering assembly, camera module and electronic device

Info

Publication number: WO2023051476A1
Application number: PCT/CN2022/121458
Authority: WO
Inventors: 李松杰; 王丹
Original assignee: 维沃移动通信有限公司
Priority date: 2021-09-29
Filing date: 2022-09-26
Publication date: 2023-04-06
Also published as: CN113759636A; CN113759636B

Abstract

Disclosed in the present application are a filtering assembly, a camera module and an electronic device. The filtering assembly comprises: a first substrate, a second substrate, a filtering layer, a first electrode, a second electrode, and a liquid crystal layer, wherein the liquid crystal layer is arranged between the first electrode and the second electrode; the first substrate is arranged on the side of the first electrode that is away from the liquid crystal layer; the second substrate is connected to the side of the second electrode that is away from the liquid crystal layer; the light transmittance of the liquid crystal layer is adjustable; and the filtering layer is arranged between the first substrate and the first electrode.

Description

Filter components, camera modules and electronic equipment

Cross References to Related Applications

This application claims the priority of the Chinese patent application with application number 202111168546.4 and titled "Optical Filter Assembly, Camera Module and Electronic Equipment" filed with the China Patent Office on September 29, 2021, the entire contents of which are incorporated herein by reference. Applying.

technical field

The application belongs to the technical field of electronic equipment, and in particular relates to a filter assembly, a camera module and electronic equipment.

Background technique

In recent years, with the rapid development of the technology of smart electronic devices, users' demand for electronic devices is also increasing, and at the same time, the requirements for the experience of electronic devices are also getting higher and higher. Among them, the camera function is more concerned by users, and the functions of the camera modules of electronic devices are becoming more and more abundant, but the requirements of users for the camera modules are also getting higher and higher.

At present, commonly used camera modules can realize the function of automatic zooming, usually by means of driving parts to drive the movement of the lens. However, disposing the driver in the camera module may easily result in larger size and higher power consumption of the camera module.

Contents of the invention

The purpose of this application is to provide a filter assembly, camera module and electronic equipment, at least to solve the problems in the prior art that the driver is installed in the camera module, which easily causes the size of the camera module to be large and the power consumption is high one.

In order to solve the above-mentioned technical problems, the application is implemented as follows:

In the first aspect, an embodiment of the present application proposes a filter assembly, including: a first substrate, a second substrate, a filter layer, a first electrode, a second electrode, and a liquid crystal layer, wherein,

The liquid crystal layer is disposed between the first electrode and the second electrode, the first substrate is disposed on a side of the first electrode away from the liquid crystal layer, and the second substrate is connected to the The second electrode is away from the side of the liquid crystal layer, and the light transmittance of the liquid crystal layer can be adjusted;

The filter layer is disposed between the first substrate and the first electrode.

In a second aspect, the embodiment of the present application provides a camera module, including: the above-mentioned filter assembly.

In a third aspect, the embodiment of the present application provides an electronic device, including: the above-mentioned filter assembly.

In an embodiment of the present application, the liquid crystal layer is disposed between the first electrode and the second electrode, and the first substrate is disposed on a side of the first electrode away from the liquid crystal layer, so The second substrate is connected to the side of the second electrode away from the liquid crystal layer, and the filter layer is arranged between the first substrate and the first electrode, so that the first substrate, the The filter layer, the first electrode, the liquid crystal layer, the second electrode, and the second substrate are sequentially stacked to form the filter assembly, and the filter assembly can achieve specific filtering through the filter layer. wavelength of light. When the filter assembly is applied to the camera technology, the shooting effect of the camera module can be improved; and because the light transmittance of the liquid crystal layer can be adjusted, the focal length of the camera module can be adjusted, and the camera module can be realized. The zoom function of the camera group does not need to set the driver to drive the lens movement, which can avoid the problems of large size and high power consumption of the camera module caused by the driver.

Additional aspects and advantages of the application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the application.

Description of drawings

The above and/or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, wherein:

FIG. 1 is a schematic structural view of a filter assembly according to an embodiment of the present application;

Fig. 2 is a schematic structural diagram of a camera module according to an embodiment of the present application;

FIG. 3A is a schematic structural diagram of a filter layer according to an embodiment of the present application;

3B is a schematic structural diagram of a first alignment film according to an embodiment of the present application;

FIG. 3C is a schematic structural diagram of a second alignment film according to an embodiment of the present application;

FIG. 3D is a schematic structural diagram of a first electrode according to an embodiment of the present application;

4 is a schematic structural diagram of a liquid crystal layer according to an embodiment of the present application;

FIG. 5 is a schematic structural diagram of another liquid crystal layer according to an embodiment of the present application.

Reference signs:

100-filter assembly, 1-first substrate, 2-filter layer, 21-color channel, 3-first alignment film, 31-first polarizing region, 4-first electrode, 41-first electrode unit, 5-liquid crystal layer, 51-liquid crystal region, 6-second electrode, 7-second alignment film, 71-second polarizing region, 8-second substrate, 200-lens, 300-photosensitive chip.

specific embodiment

Embodiments of the present application will be described in detail below, examples of which are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary, and are only for explaining the present application, and should not be construed as limiting the present application. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

The features of the terms "first" and "second" in the description and claims of the present application may explicitly or implicitly include one or more of these features. In the description of the present application, unless otherwise specified, "plurality" means two or more. In addition, "and/or" in the specification and claims means at least one of the connected objects, and the character "/" generally means that the related objects are an "or" relationship.

In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "upper", "lower", and "radial" are based on the orientations or positional relationships shown in the drawings, and are only In order to facilitate the description of the present application and simplify the description, it does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.

In the description of this application, it should be noted that unless otherwise specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it may be mechanically connected or electrically connected; it may be directly connected or indirectly connected through an intermediary, and it may be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in this application in specific situations.

In practical applications, the camera module usually includes a lens, a filter, and a photosensitive chip. The filter can be arranged between the lens and the photosensitive chip, and the lens can refract and converge light. , the filter can change the color of the image captured by the photosensitive chip. The photosensitive chip is the core device of the camera module, which can convert the received optical signal into an electrical signal and perform calculation processing. Specifically, the light collected by the lens passes through the filter and enters the photosensitive chip for photoelectric conversion, which can realize the shooting function of the camera module.

The filter assembly, the camera module and the electronic device of the embodiment of the present application are described below with reference to FIGS. 1-5 .

As shown in FIG. 1 , in the first aspect, in some embodiments of the present application, a filter assembly is disclosed, which may specifically include: a first substrate 1 , a second substrate 8 , a filter layer 2 , and a first electrode 4 , the second electrode 6 and the liquid crystal layer 5, wherein the liquid crystal layer 5 is arranged between the first electrode 4 and the second electrode 6, the first substrate 1 is arranged on the side of the first electrode 4 away from the liquid crystal layer 5, and the second substrate 8 is connected to the side of the second electrode 6 away from the liquid crystal layer 5 , the light transmittance of the liquid crystal layer 5 can be adjusted; the filter layer 2 is arranged between the first substrate 1 and the first electrode 4 .

In the embodiment of the present application, the liquid crystal layer 5 is arranged between the first electrode 4 and the second electrode 6, the first substrate 1 is arranged on the side of the first electrode 4 away from the liquid crystal layer 5, and the second substrate 8 is connected to the first electrode 4. The second electrode 6 is away from the side of the liquid crystal layer 5, and the filter layer 2 is arranged between the first substrate 1 and the first electrode 4, so that the first substrate 1, the filter layer 2, the first electrode 4, the liquid crystal layer 5, the first electrode 4 The two electrodes 6 and the second substrate 8 are sequentially stacked to form a filter assembly 100 , and the filter assembly 100 can filter light of a specific wavelength through the filter layer 2 . When the filter assembly 100 is applied to the camera technology, the shooting effect of the camera module can be improved; and because the light transmittance of the liquid crystal layer 5 can be adjusted, the focal length of the camera module can be adjusted, and the camera module can be realized. For the zoom function, there is no need to set the driver to drive the lens 200 to move, which can avoid the problems of large size and high power consumption of the camera module caused by the driver.

Specifically, in the embodiment of the present application, the electrical signal between the first electrode 4 and the second electrode 6 is adjustable, and by changing the voltage value between the first electrode 4 and the second electrode 6, the liquid crystal layer 5 can be changed. Transmittance.

Alternatively, the second electrode 6 can also be eliminated, and one side of the liquid crystal layer 5 is connected to the first electrode 4, and the other side is grounded. In this way, the light transmission of the liquid crystal layer 5 can be changed by adjusting the voltage value of the first electrode 4. Rate.

As shown in FIG. 2 , the camera module can be formed by a combination of an optical filter assembly 100 , a lens 200 and a photosensitive chip 300 , and the optical filter assembly 100 can be arranged between the lens 200 and the photosensitive chip 300 .

Specifically, the filter assembly 100 may include: a multilayer structure such as a first substrate 1, a second substrate 8, a filter layer 2, a first electrode 4, a second electrode 6, and a liquid crystal layer 5, which can improve the performance of the filter assembly 100. Structural strength, when it is applied to camera technology, can improve the stability of camera module shooting.

Specifically, since the filter assembly 100 includes the liquid crystal layer 5 , the manufacturing method of the filter assembly 100 can refer to the manufacturing method of a liquid crystal screen in the prior art, which is not specifically limited in this embodiment of the present application.

Further, the liquid crystal layer 5 may include liquid crystal molecules, and the liquid crystal molecules have the characteristic of electrically variable refractive index. When the voltage difference on both sides of the liquid crystal layer 5 changes, the orientation of the liquid crystal molecules changes, and the liquid crystal layer can be changed. A refractive index of 5, that is, the optical path of the light changes, which can realize the auto-focus function of the camera module.

Specifically, the cross-sectional shape of the liquid crystal molecules may be oval, circular, rectangular, etc., which is not specifically limited in the embodiment of the present application, as long as the refractive index of the liquid crystal molecules in different directions is different. Taking the cross-sectional shape of the liquid crystal molecule as an ellipse as an example, the following description is made, and other settings can be referred to: when the long axis of the liquid crystal molecule is perpendicular to the plane of the first substrate 1, the refractive index can be the largest, and the long axis of the liquid crystal molecule is parallel to the first substrate 1 The refractive index of the plane is the smallest, and the refractive index of liquid crystal molecules is positively correlated with the alignment angle (the angle between the long axis and the plane of the first substrate 1), and the size of the alignment angle can be related to the first electrode 4 and the second electrode 6. Correlation between electrical signals.

Specifically, the first substrate 1, the second substrate 8, the filter layer 2, the first electrode 4, the second electrode 6, and the liquid crystal layer 5 can all have good light transmittance, and the filter layer 2 can control the transmission of specific wavelengths. light.

According to some other embodiments of the present application, the first electrode 4 may be provided with a plurality of independently arranged first electrode units 41, and the second electrode 6 may be provided with a plurality of independently arranged second electrode units 61 correspondingly. The liquid crystal layer 5 Can include a plurality of liquid crystal regions 51; the first electrode unit 41 and the second electrode unit 61 are arranged in one-to-one correspondence; the liquid crystal region 51 is correspondingly arranged between the first electrode unit 41 and the second electrode unit 61; wherein, in the first electrode unit When the electrical signal between the unit 41 and the second electrode unit 61 changes, the light transmittance of the corresponding liquid crystal region 51 can be adjusted.

In the embodiment of the present application, the liquid crystal region 51 is correspondingly arranged between the first electrode unit 41 and the second electrode unit 61, and when the electrical signal between the first electrode unit 41 and the second electrode unit 61 changes, The light transmittance of the corresponding liquid crystal region 51 can be adjusted. When the filter assembly 100 is applied to the imaging technology, by adjusting the light transmittance of different liquid crystal regions 51, aberration, distortion, curvature of field, uneven brightness, etc. can be avoided phenomenon, optimize the final image quality, and improve the shooting effect.

As shown in Figure 5, the liquid crystal layer 5 may include four liquid crystal regions 51: N1, N2, N3 and N4, N1, N2, N3 and N4 respectively correspond to different electrical signals, for example, the direction from N1 to N2 corresponds to The light transmittance of the liquid crystal region 51 can be sequentially decreased, sequentially increased, alternately changed, etc., specifically determined according to the brightness of the light collected by the lens 200, which can achieve uniform brightness of the imaging surface of the photosensitive chip 300 and improve the imaging effect.

Specifically, since the light transmittance of different liquid crystal regions 51 can be adjusted independently, the filter assembly 100 can realize the function of a variable aperture, so that the camera module can achieve multi-functional shooting effects such as main camera shooting, wide-angle shooting, and telephoto shooting. .

Optionally, the filter assembly 100 may include a first alignment film 3 and a second alignment film 7; the first alignment film 3 may be disposed between the filter layer 2 and the first electrode 4, and the second alignment film 7 may be disposed between between the second electrode 6 and the second substrate 8 .

In the embodiment of the present application, the use of the first alignment film 3 and the second alignment film 7 can control the transmission of light that is consistent with its polarization state, and can reduce the crosstalk between different colors of light. During the shooting process, no crosstalk can be obtained. The color image can improve the shooting effect of the camera module.

Specifically, the orientation of the first alignment film 3 and the orientation of the second alignment film 7 can be parallel, perpendicular, or at any angle, which can be set according to actual needs, which is not specifically limited in this embodiment of the present application.

Optionally, the first alignment film 3 may be provided with a plurality of first polarization regions 31, the second alignment film 7 may be provided with a plurality of second polarization regions 71 correspondingly, and the filter layer 2 may be provided with a plurality of color channels 21; Both the first polarization area 31 and the second polarization area 71 can be set corresponding to the color channel 21 .

In the embodiment of the present application, the light passing through the color channel 21 can pass through the first polarization region 31 and the second polarization region 71 in sequence. The crosstalk between them improves the shooting effect of the camera module.

Specifically, the filter layer 2, the first alignment film 3, the first electrode 4, the second electrode 6, and the second alignment film 7 are all correspondingly arranged, and the color channels 21 of the filter layer 2 can be arranged periodically, as shown in FIG. 3A, One of the arrangement periods is shown, and one arrangement period includes four color channels 21: R (red, red) channel, two G (green, green) channels and B (blue, blue) channel. As shown in Figure 3B, the first alignment film 3 includes four corresponding first polarizing regions 31, and the orientation of each first polarizing region 31 is shown in the direction of the arrow in Figure 3B; as shown in Figure 3C, the second orientation The film 7 includes corresponding four second polarizing regions 71 , each of which is oriented as shown in the direction of the arrow in FIG. 3C . As shown in Figure 3D, the projections of the first electrode unit 41 and the second electrode unit 61 overlap, and the electrical signals between the first electrode unit 41 and the second electrode unit 61 include: U1, U2, U3 and U4, U1, U2 , U3 and U4 are set corresponding to the four color channels 21 respectively.

Specifically, U1 can control the rotation of liquid crystal molecules in the liquid crystal region 51 corresponding to the R channel, U2 and U3 can respectively control the rotation of liquid crystal molecules in the liquid crystal region 51 corresponding to the two G channels, and U4 can control the rotation of the liquid crystal molecules in the liquid crystal region 51 corresponding to the B channel. Liquid crystal molecules in the liquid crystal region 51 rotate. Since the liquid crystal molecules have the ability to rotate the polarization direction of the incident light, changing the values of U1, U2, U3 and U4 can change the rotation angle of the liquid crystal molecules, thereby changing the rotation angle of the polarization direction of the incident light, and realizing the cycle of the color channel 21 sex cut off.

For example, assuming that the orientations of the first alignment film 3 and the second alignment film 7 are perpendicular to each other, a voltage U1 is applied to the liquid crystal region 51 corresponding to the R channel, and the liquid crystal molecules rotate, so that the polarization direction of the light is rotated by 90 degrees, and the light can pass through the second orientation The film 7 is irradiated onto the photosensitive chip 300 . No voltage is applied to the liquid crystal region 51 corresponding to the G channel and the B channel, that is, U2=U3=U4=0, then the liquid crystal molecules in the liquid crystal region 51 corresponding to the G channel and the B channel do not rotate, and the corresponding light polarization direction does not rotate. Then the light corresponding to the G channel and the B channel cannot be irradiated to the photosensitive chip 300 through the second alignment film 7, which realizes the periodic cutoff of the different color channels 21, that is, the photosensitive chip 300 can obtain monochromatic color through the light of the R channel. image, avoiding the crosstalk between G channel and B channel. The monochrome images of G channel and B channel can also be obtained in time sequence, and the final color image can be fused with the help of multi-frame rate monochrome images in the later stage. Ensuring the matching of the voltage control and the response speed of the liquid crystal molecules can ensure that a three-color image of the same scene can be obtained within a short time interval.

Optionally, a plurality of liquid crystal regions 51 can be arranged concentrically. In the embodiment of the present application, a plurality of liquid crystal regions 51 are concentrically arranged to facilitate the control of light transmittance of each liquid crystal region 51 to realize the zoom function of the camera module.

Specifically, the light transmittance corresponding to the liquid crystal region 51 can be controlled separately to realize a variable aperture, and the number of apertures can be flexibly adjusted to realize different shooting functions such as main camera, wide-angle, and telephoto. When setting the number of apertures, the liquid crystal layer 5 can be divided into a plurality of liquid crystal regions 51 symmetrically and outwardly around the physical center of the liquid crystal layer 5 . Different liquid crystal regions 51 can be provided with the first electrode unit 41 and the second electrode unit 61 correspondingly. By adjusting the electrical signal between the first electrode unit 41 and the second electrode unit 61, the aperture size of the light transmission hole can be adjusted to realize variable aperture.

As shown in FIG. 4 , the structure of the liquid crystal layer 5 may be circular, and along its radial direction, the liquid crystal layer 5 may be divided into two liquid crystal regions 51 : a circular region and an annular region. When the electrical signal between the first electrode unit 41 and the second electrode unit 61 is set to U5, the light can pass through; when the electrical signal between the first electrode unit 41 and the second electrode unit 61 is U6, the light can not pass through , to realize the "on" and "off" of the light. When the electrical signal of the circular area and the ring area are both U5, the light transmission aperture is larger; when the electrical signal corresponding to the circular area is U5, and the electrical signal corresponding to the ring area is U6, the light transmission aperture is smaller. FIG. 4 is only an example where the number of apertures is 2. For other situations, reference may be made to the setting, which is not specifically limited in this embodiment of the present application.

Optionally, the shape of the liquid crystal region 51 may include: at least one of circle, rectangle, ring and irregular polygon.

In the embodiment of the present application, the shape of the liquid crystal region 51 includes at least one of circle, rectangle, ring and irregular polygon, which can increase the diversity of the configuration of the liquid crystal region 51 and realize light transmission holes of different shapes.

In some other embodiments of the present application, the filter assembly 100 may include a controller, and the controller may be electrically connected to the first electrode unit 41 and the second electrode unit 61 respectively, and may be used to adjust the first electrode unit 41 and the magnitude of the electrical signal between the second electrode unit 61.

In the embodiment of the present application, it is more convenient and faster to use the controller to adjust the magnitude of the electric signal between the first electrode unit 41 and the second electrode unit 61 , and the sensitivity is higher.

In some other embodiments of the present application, the filter assembly 100 may include a packaging structure, and the first substrate 1, the second substrate 8, the filter layer 2, the first electrode 4, the second electrode 6 and the liquid crystal layer 5 are all packaged in within the package structure.

In the embodiment of the present application, the package structure can fix and seal the first substrate 1, the second substrate 8, the filter layer 2, the first electrode 4, the second electrode 6 and the liquid crystal layer 5, and To protect the effect, the structural stability of the filter assembly 100 can be improved.

Specifically, the packaging structure may be a plastic part or a metal part, which may be set according to actual requirements, which is not specifically limited in this embodiment of the present application.

The filter assembly described in the embodiments of the present application at least includes the following advantages:

In an embodiment of the present application, the liquid crystal layer is disposed between the first electrode and the second electrode, and the first substrate is disposed on a side of the first electrode away from the liquid crystal layer, so The second substrate is connected to the side of the second electrode away from the liquid crystal layer, and the filter layer is arranged between the first substrate and the first electrode, so that the first substrate, the The filter layer, the first electrode, the liquid crystal layer, the second electrode, and the second substrate are sequentially stacked to form the filter assembly, and the filter assembly can achieve specific filtering through the filter layer. wavelength of light. When the filter assembly is applied to the camera technology, the shooting effect of the camera module can be improved; and because the light transmittance of the liquid crystal layer can be adjusted, the focal length of the camera module can be adjusted, and the camera module can be realized. The zoom function of the module does not need to set the driver to drive the lens movement, which can avoid the problems of large size and high power consumption of the camera module caused by the driver.

In the second aspect, the embodiment of the present application further provides a camera module, which may specifically include the above-mentioned filter assembly.

The camera module described in the embodiment of the present application at least includes the following advantages:

In a third aspect, the embodiment of the present application further provides an electronic device, which may specifically include the above-mentioned filter assembly.

The electronic equipment described in the embodiments of the present application at least includes the following advantages:

In the description of this specification, references to the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific examples," or "some examples" are intended to mean that the implementation A specific feature, structure, material, or characteristic described by an embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations 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 any one or more embodiments or examples.

Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present application. The scope of the application is defined by the claims and their equivalents.

Claims

A filter assembly, including: a first substrate, a second substrate, a filter layer, a first electrode, a second electrode, and a liquid crystal layer, wherein,

The liquid crystal layer is disposed between the first electrode and the second electrode, the first substrate is disposed on a side of the first electrode away from the liquid crystal layer, and the second substrate is connected to the The second electrode is away from the side of the liquid crystal layer, and the light transmittance of the liquid crystal layer can be adjusted;

The filter layer is disposed between the first substrate and the first electrode.
The optical filter assembly according to claim 1, wherein the first electrode is provided with a plurality of independently arranged first electrode units, and the second electrode is correspondingly provided with a plurality of independently arranged second electrode units, the The liquid crystal layer includes a plurality of liquid crystal regions;

The first electrode unit and the second electrode unit are provided in one-to-one correspondence;

The liquid crystal region is correspondingly arranged between the first electrode unit and the second electrode unit;

Wherein, when the electrical signal between the first electrode unit and the second electrode unit changes, the light transmittance of the corresponding liquid crystal region can be adjusted.
The filter assembly according to claim 2, wherein the filter assembly comprises a first alignment film and a second alignment film;

The first alignment film is arranged between the filter layer and the first electrode, and the second alignment film is arranged between the second electrode and the second substrate.
The filter assembly according to claim 3, wherein the first alignment film is provided with a plurality of first polarization regions, the second alignment film is correspondingly provided with a plurality of second polarization regions, and the filter layer is provided with There are multiple color channels;

Both the first polarization area and the second polarization area are set corresponding to the color channels.
The filter assembly according to claim 2, wherein a plurality of said liquid crystal regions are arranged concentrically.
The filter assembly according to claim 5, wherein the shape of the liquid crystal region comprises: at least one of a circle, a rectangle, a ring and an irregular polygon.
The filter assembly according to claim 2, wherein the filter assembly includes a controller, the controller is electrically connected to the first electrode unit and the second electrode unit, and is used to adjust the first electrode unit and the second electrode unit. The magnitude of the electrical signal between the first electrode unit and the second electrode unit.
The optical filter assembly according to claim 1, wherein the optical filter assembly includes a packaging structure, and the first substrate, the second substrate, the filter layer, the first electrode, the second electrode and the liquid crystal layer are all encapsulated in the within the package structure described above.
A camera module, comprising: the filter assembly described in any one of claims 1-8.
An electronic device, comprising: the filter assembly according to any one of claims 1-8.