Infrared imaging assembly

Abstract

Infrared imaging assembly (1) comprising an infrared beam shifting unit (4) and an infrared image sensor (2) comprising a plurality of pixels (3), wherein the infrared beam shifting unit (4) and the infrared image sensor (2) are located along a beam axis (6) and wherein the shifting unit (4) comprises a window (5), which is tiltably mounted about a first tilting axis (7) which lies within the plane of the window and wherein the window (5) is configured to shift an infrared beam (9) passing through the window (5) along the infrared beam axis (6) onto the image sensor by a fraction of a pixel (3) size and as a function of a tilt about the first tilting axis (7).

Description

[0001] Infrared imaging assembly

[0002] Description

[0003] The invention relates to an infrared imaging assembly.

[0004] Infrared imaging assemblies typically are used to capture and visualize infrared radiation, which is not visible to the human eye. This typically takes place by using sensors that are capable of detecting heat emitted by an object and converting it into an image representation. These infrared imaging assemblies may consist of various components, including an infrared sensor. The infrared sensor detects the infrared radiation emitted by objects and converts it into electrical signals. Optics may focus the infrared radiation onto the sensor, and an electronics unit processes the signal and converts it into a visual representation.

[0005] With infrared imaging assemblies, it is desirable to achieve a high spatial resolution of the captured infrared data, which is typically achieved by providing an infrared sensor with a high spatial resolution. At the same time, there is a need to reduce the size of the infrared image sensor. However, these goals and their achievement are opposed to each other and are only achievable with high technological effort.

[0006] It is an objective of the invention to suggest an infrared imaging assembly which simultaneously allows to capture infrared data with a comparable quality that is typically achieved by sensors with a high spatial resolution and which at the same time has a small size.

[0007] The objective is solved by an infrared imaging sensor according to claim 1 and an infrared beam shifting unit according to claim 23. Preferred embodiments are subject-matters of dependent claims.

[0008] According to the invention, the infrared imaging assembly comprises an infrared beam shifting unit and an infrared image sensor comprising a plurality of pixels, wherein the infrared beam shifting unit and the infrared image sensor are located along a beam axis and wherein the shifting unit comprises a window, which is tiltably mounted about at least a first tilting axis and wherein the window is configured to shift an infrared beam passing through the window along the infrared beam axis onto the image sensor by a fraction of a pixel and as a function of a tilt of the window about the first tilting axis. It is an advantage of the invention that by means of the infrared imaging assembly it is possible to achieve data with a high spatial resolution without increasing the physical resolution of the infrared image sensor and without increasing its size.

[0009] According to the invention, the term “spatial resolution” may be understood as a level of detail or the smallest discernible features that can be captured by the infrared image sensor. In other words, it is a measure of how well a sensor can distinguish between closely spaced objects or details in an image. Therefore, the spatial resolution describes the ability of a sensor to resolve fine details and spatially separate different objects or structures within an image.

[0010] As mentioned above, the infrared image sensor comprises a plurality of pixels that may be arranged in a row or a plurality of rows, defining a pixel matrix. The term pixel preferably refers to the smallest sensor elements of the sensor, whereby at least their respective size and their distance to each other determine the physical sensor resolution of the sensor.

[0011] The shifting unit is a device by means of which, when tilted, it is possible to shift an infrared beam passing through the shifting unit onto the infrared image sensor. In particular, the dimensions of the window and the distance between the window and the infrared image sensor are chosen such that tilting the window about the first tilting axis causes a displacement of the beam on the infrared image sensor that is smaller than the dimension of a pixel along the direction of displacement of the infrared beam on its surface.

[0012] A displacement of the infrared beam may cause a spot, which results from the projection of the infrared beam on the image sensor surface, to be shifted to the extent that it can be partially directed from one of the pixels of the sensor to an adjacent pixel. In particular, each of the pixels comprises slightly different information compared to each other. In a low resolution approximation, the information of the sub-images appear to be identical. However, by evaluating the signals of adjacent pixels, the resolution of the image sensor is increased.

[0013] In particular, the window comprises two optical surfaces, preferably facing away from each other and in particular such that a first surface faces the infrared image sensor and a second surface faces away from the infrared image sensor.

[0014] Preferably, in at least one state of the window, in particular in an untilted state, a main extension plane of the window extends essentially parallel to the infrared image sensor.

[0015] The infrared imaging assembly may also comprise an actuator, which is designed to tilt the window about the first tilting axis between at least to tilted positions with a cycle frequency. The cycle frequency may be considered as a frequency that defines how often the tilted position is changed within a predefined period of time or how often all possible tilted positions are changed within a predefined period of time.

[0016] In a preferred embodiment, the window is designed to have a transparency of more than 80 percent, preferably of more than 90 percent, and in particular preferably more than 95 percent, in a wavelength range between 8 pm and 14 pm.

[0017] In another preferred embodiment, the window is designed to have a transparency of more than 80 percent, preferably of more than 90 percent, and in particular preferably more than 95 percent, in a wavelength range between 0.75 to 2.5 pm.

[0018] In another preferred embodiment, the window is designed to have a transparency of more than 80 percent, preferably of more than 90 percent, and in particular preferably more than 95 percent, in the wavelength range between 2 to 6 pm.

[0019] Studies have shown that the above-described wavelength ranges can be advantageous for different applications of infrared image assembly and that realization of the individual ranges 8 pm and 14 pm or from 0.75 to 2.5 pm or from 0.75 to 2.5 pm are advantageous in terms of manufacturing and material costs in the production of the window. However, it is within the scope of the invention, that a window may be designed covering the entire range of 0.75 pm to 14 pm or a part of it with a transparency of more than 80 percent, preferably more than 90 percent, in particular more than 95 percent.

[0020] In a preferred embodiment, the window is made of a material that comprises Germanium or Silicon or Gallium Arsenide or which essentially consists of Germanium or Silicon Gallium Arsenide.

[0021] By utilizing a window made from a material that includes Germanium, Silicon, Gallium Arsenide, or primarily consists of Germanium or Silicon Gallium Arsenide, the device or system can take advantage of the specific properties of these materials. In particular, studies of the applicant have shown that these materials In particular, investigations by the applicant have shown that the materials mentioned have good transparency for infrared radiation.

[0022] In a preferred embodiment the pixels each have a size of 10 to 20 pm. Preferably the shifting unit is configured to shift the infrared beam by 0.2 to 0.8 of the pixel size.

[0023] The aforementioned ratios between the pixel size and / or the displacement of the infrared beam to be achieved have proven to be particularly advantageous for achieving a high overall resolution of the infrared imaging assembly at a comparatively low physical resolution of the infrared image sensor. In a preferred embodiment, the window comprises a material with a refractive index of more than 1.6, in particular more than 2.0 and preferably more than 3.0.

[0024] The above-described advantageous further development is based on the realization that the tilting of the window about the first axis can be comparatively small in order to achieve the desired displacement of the infrared beam on the surface of the infrared image sensor, if the window is made of a material with a high refractive index. The above refractive indices above 1.6 have proven to be particularly advantageous in practical testing.

[0025] In a preferred embodiment, the first optical surface of the window and the second optical surface of the window are at least 2.5 mm, in particular 3.0 mm and preferably 5 mm spaced apart from each other.

[0026] The above-described embodiment is based on the realisation that the thickness of the window can have a positive effect on how much the window must be tilted about the first tilting axis to cause a desired displacement of the infrared beam on the surface of the infrared image sensor. In particular, an increasing thickness of the window requires a smaller tilting angle to cause a desired displacement of the infrared beam than with a comparatively thinner window.

[0027] In a preferred embodiment, the first optical surface and / or the second optical surface is coated with an anti-reflection coating, which is configured to have a reflectivity of less than 20 preferably less than 10 and most preferably less than 5 percent between 8 to 14 pm or 0.75 to 2.5 pm or 2 to 6 pm. In particular, the antireflection coating is selected in such a way that it prevents reflection of infrared radiation.

[0028] In a preferred embodiment, the image sensor comprises a pixel row and several additional pixel columns arranged at an angle of more than 45° and less than 135° with respect to the direction of the pixel row. The term “several additional pixel columns” could be understood as anumber of columns of at least 50 percent of a pixel count in a pixel row and most 200 percent of the pixel count in the pixel row.

[0029] The above-described embodiment refers to the image sensor, which comprises a plurality of pixels that extend in a sensor plane. In a simple embodiment, the columns are arranged in an angle of approximately 90° degrees with respect to the pixel row. However, the embodiment is not limited to such an arrangement. Therefore, according to another embodiment the columns are aligned parallel to each other but in an angle within the range between 45° and 135°. It is also within the scope of the embodiment that the columns are not arranged parallel to each other and with different angles with respect to the pixel row in said range. In another preferred embodiment, the window is tiltably mounted about a second tilting axis, which lies within the plane of the window and the window shifts the infrared beam by a fraction of the pixel at an angle of more than 45° and less than 135° with respect to the direction of the pixel row.

[0030] In a preferred embodiment, the shifting unit is configured to have a cycling frequency of 5 to 50 hertz, preferably 10 to 40 Hertz. In an embodiment, wherein the window is tilted about the first tilting axis only, the cycling frequency defines an amount of position changes between a first and a second tilted position of the window about the first tilting axis a second. In an embodiment, wherein the window is tilted about the first and the second tilting axis, a total of four tilt positions may be set for the window. Here, the cycling frequency defines an amount of position changes between the four tilt positions in a second.

[0031] In a preferred embodiment, the infrared imaging assembly has an operation state, in which the shifting unit does not perform a time dependent shifting and the image sensor is in a state of imaging.

[0032] According to the above-described embodiment, the infrared image sensor is operated only when the window is at rest in one of its tilted positions about the first and / or the second tilting axis. In other words, the operation of the infrared imaging assembly is discrete and in particular not continuous. Preferably, the image sensor generates several images during a rest state of the shifting unit. The term “several images” could be understood as a number of images between two and ten.

[0033] In a preferred embodiment, the infrared imaging assembly comprises an actuator. In general, the invention is not limited to specific type of actuator. The actuator may therefore by a magnetic force-based actuator, in particular an electromagnetic actuator, a shape memory alloyed based actuator or a piezo based actuator.

[0034] A magnetic force-based actuator may comprise a coil and a magnet, wherein the magnet is mechanically coupled to the window and the coil is mechanically coupled to a component of the infrared imaging assembly, which is fixedly arranged with respect to the window. The coil and the magnet are preferably arranged such that, when an electric current passes the coil, a magnetic force is generated that interacts with the magnetic field of the magnet and forces the window to be tilted about the first and / or the second tilting axis. Preferably, the infrared imaging assembly comprises more than one magnet and more than one coil, in particular two, three or four magnets and coils respectively.

[0035] In particular, the coils may be arranged such that they face away from the infrared imaging sensor. This is advantageous, since an electric current that passes through the coils may generate heat that may disturb the operation of the infrared image sensor. However, by arranging the coils such that they face away from the infrared imaging sensor, such a disturbance can be avoided. In a preferred embodiment, the infrared imaging assembly comprises a thermal insulation, which is located between the shifting unit and the image sensor. Preferably, the actuator is located on a side of the shifting unit facing away from the infrared image sensor.

[0036] Preferably, the infrared imaging assembly comprises a control unit, which is configured to control the shifting unit, in particular by providing signals and / or electrical energy to the actuator or plurality of actuators in order to control the shifting unit. In particular, the control unit may be configured to control the infrared image sensor, in particular as a function of a tilting position of the window, in particular in order to enable a discrete operation as described herein.

[0037] Preferably, the shifting unit comprises a control element, which is connected to the control unit at least by means of a signal connection. The control element preferably comprises at least a switch, which is configured to set the control unit between at least two functional states, for example to turn the shifting unit on and off.

[0038] One advantage of the above-mentioned control unit is that the infrared imaging assembly can be operated in different modes, for example by setting the shifting unit for different shifting characteristics, such as a shifting amplitude and / or frequency. This for example allows to take into account a scanning frequency of the infrared sensor or its pixel size.

[0039] It is also possible to switch the shifting unit on and off using the switch. This makes it possible to operate the infrared imaging assembly either with or without a shifting of an infrared beam. In a switched-off state, there is no movement of the infrared beam shifting unit and therefore no adjustment of the infrared beam. This particularly favors the use of the infrared beam shifting unit in infrared imaging assemblies, which require different resolutions during operation, for example depending on the application. The preferred embodiment is not limited to a specific kind of control element or its switch, may for example be of mechanical type. In particular, the shifting unit can be switched off if an object, which shall be detected by means of the infrared imaging assembly, moves at a speed relative to the imaging assembly or at least its infrared sensor. Investigations by the applicant have shown that an adjustment of the shifting unit can be advantageous here in order to avoid undesirable blurring effects.

[0040] Preferably, the infrared imaging assembly comprises a cooling system, which is at least thermally connected to the shifting unit. The cooling system may comprise a passive component such as cooling fins, which are thermally coupled to a shifting unit and which are designed to cool the shifting unit. Additionally or alternatively, the cooling system may comprise an active component, such as a fluid system with a circulating coolant, that may be thermally coupled to the shifting unit and is preferably controlled by the control unit.

[0041] Preferably, the window is held by a frame. The window may have a square or rectangular geometry in its extension plane. The frame may hold the window at least in its corner regions and / or its edges and preferably be mounted to a housing of the infrared imaging assembly such that the window is tiltable about the first and / or the second tilting axis. In particular, the frame is mounted by at least one, preferably multiple, spring elements that are designed in order to provide a rotational degree of freedom about the first and / or the second tilting axis. The spring elements may at least partially be planar sheet metal elements.

[0042] In an embodiment, wherein the actuator is a shape memory alloy actuator, an element, which is mechanically coupled to the frame may be made of a shape memory alloy, which has a geometry that depends on the temperature of the shape memory alloy and may be set as a function of an electric current that passes through said element.

[0043] In an embodiment, wherein the actuator is a piezo based actuator, a piezo element may be coupled to the frame. By applying an electrical voltage to the piezo based actuator an actuation force may be exerted to the frame, causing a tilting movement about the first and / or the second tilting axis.

[0044] In a preferred embodiment, the shifting unit comprises a temperature sensor. The temperature sensor may be used to detect an ambient temperature of the shifting unit or the entire infrared imaging assembly. This is advantageous, since the temperature data may be used to compensate a temperature dependent drift of the infrared image sensor and / or the window and / or the shifting unit.

[0045] As mentioned above, the objective of the invention is also solved by an infrared beam shifting unit. According to the invention, the infrared beam shifting unit comprises a window, which is tiltably mounted about a first tilting axis, which lies within a plane of the window and wherein the window is configured to laterally shift an infrared beam passing through the window along an infrared beam axis as a function of a tilt about the first tilting axis.

[0046] In particular, the above-described infrared beam shifting unit is suitable for use in an infrared imaging assembly according to the invention or a preferred embodiment thereof. The explanations in connection with the achievable advantages of the infrared beam shifting unit described herein may therefore apply accordingly.

[0047] In a preferred embodiment, the infrared beam shifting unit comprises at least an actuator and a control unit, which is configured to control the shifting unit, in particular by providing signals and / or electrical energy to the actuator and wherein shifting unit further comprises a control element, which is connected to the control unit at least by means of a signal connection.

[0048] A control unit of the type described above can be used to control the actuator and to supply it with electrical energy in order to effect the desired adjustment of the window. In particular, it is possible to control the operation of the infrared beam shifting unit depending on an input by an operator at the control element, for example by specifying how the desired movement of the infrared beam shifting unit is to be generated. Preferably, a tilting amplitude of the shifting movement or a tilting frequency can be set.

[0049] Preferably, the control element comprises at least a switch, which is configured to set the control unit between at least two functional states, in particular to turn the shifting unit on and off.

[0050] The embodiment of the infrared beam shifting unit described above improves the operation of infrared imaging assemblies in particular, since the functionality of the infrared beam shifting unit can be adjusted between multiple predefined functional states. For example, it is possible that a first functional state is characterized by a first frequency and / or shift amplitude and a second functional state is characterized by a second frequency and / or shift amplitude and that the functional states can by changed as required by means of the switch.

[0051] In particular, the switch can be used to turn the infrared beam shifting unit on and off as required. In a switched-off state, there is no movement of the infrared beam shifting unit and therefore no adjustment of the infrared beam. In particular, the window of the shifting unit is not tilted with respect to a reference position. This particularly favors the use of the infrared beam shifting unit in infrared imaging assemblies, which require different resolutions during operation, for example depending on the application. In other words, the shifting unit may be turned off if a low resolution is sufficient and turned on if a higher resolution is required. In particular, the shifting unit can be switched off if a measurement object moves at a speed relative to the imaging assembly or at least its infrared sensor, or vice versa. Investigations by the applicant have shown that an adjustment of the shifting unit can be advantageous here in order to avoid undesirable blurring effects.

[0052] In addition, the use of the control element, which in particular comprises a switch, favors the integration capability of the infrared beam shifting unit into an existing device with an infrared sensor, since the infrared beam shifting unit can be adapted to the operation of the infrared sensor as required. Furthermore, as already mentioned above, the infrared sensor can also be operated without the infrared beam shifting unit if required.

[0053] Further advantages of the invention are described with respect to the figures and the embodiments shown therein. Figure 1 shows an infrared imaging assembly in a schematic side view of two states a) and b);

[0054] Figure 2 shows an infrared beam shifting unit in a first perspective view;

[0055] Figure 3 shows the infrared beam shifting unit in a second perspective view;

[0056] Figure 4 shows the infrared beam shifting unit in a side view;

[0057] Figure 5 shows the infrared beam shifting unit in a top view;

[0058] Figure 6 shows the infrared beam shifting unit with a control unit.

[0059] For a better understanding, reference signs as used in Figures 1 to 5 are explained below:

[0060] 1 Infrared imaging assembly

[0061] 2 Infrared image sensor

[0062] 3 Pixel

[0063] 4 Shifting unit

[0064] 5 Window

[0065] 6 Beam axis

[0066] 7 First tilting axis

[0067] 8 Second tilting axis

[0068] 9 Infrared beam

[0069] 10 First optical surface

[0070] 11 Second optical surface

[0071] 12 Window width

[0072] 13 Window thickness

[0073] 14 Distance between window and infrared image sensor

[0074] 15 Printed circuit board

[0075] 16 Frame

[0076] 17 Bearing element

[0077] 18 Coil

[0078] 19 Magnet

[0079] 20 Control unit

[0080] 21 Electric connection

[0081] 22 Control element

[0082] Infrared imaging assemblies are commonly used to capture and display infrared radiation, which is not visible to the human eye. This is achieved through the utilization of infrared image sensors that can detect the heat emitted by objects and convert it into a visual image. The role of the infrared sensor is to detect the infrared radiation emitted by objects and convert it into an electrical signal.

[0083] When it comes to infrared imaging assemblies, it is desirable to achieve a high spatial resolution with the infrared sensor. Simultaneously, there is a need to reduce the size of the infrared image sensor. However, these objectives are contradictory, as reducing the size of an infrared imaging sensor requires significant technological effort, and ensuring a high spatial resolution simultaneously becomes challenging.

[0084] The infrared imaging assembly 1 as schematically shown in Figure 1 enables the artificial enhancement of the spatial resolution of an infrared image sensor. This is achieved by using an transmissive element in the form of a window to deflect an incident infrared beam and thereby shift it on the surface of the imaging sensor. As a result, the infrared beam, particularly a spot corresponding to the projection of the infrared beam on the sensor's surface, is displaced between the sensor elements of a sensor, thereby increasing the sensor's sensitivity.

[0085] View a) of Figure 1 shows the infrared imaging assembly 1 in a state of the infrared imaging assembly 1 , wherein the infrared beam is not deflected. View b) of Figure 1 shows the same infrared imaging assembly 1 as shown in view a), however in a state, wherein the infrared beam is deflected.

[0086] The infrared imaging assembly 1 comprises an infrared image sensor 2 with a plurality of pixels 3. Each pixel 3 has an essentially square shape that extends in the image plane of Figure 1 . The edge lengths of the pixels 3 is 10 pm, however may be up to 20 pm.

[0087] The pixels 3 of sensor 2 are arranged in a matrix arrangement, with a plurality of rows arranged essentially parallel to each other. One of said rows is shown in a cross section in view a) of Figure 1 .

[0088] Moreover, the infrared imaging assembly 1 comprises a shifting unit, which is shown in detail in Figures 2 to 5 and comprises a window 5.

[0089] The infrared image sensor 2 and the window 5 are arranged along a beam axis 6 which corresponds to an axis along which an infrared beam 9 passes through the window 5 and impinges on the pixels 3 of the sensor 2.

[0090] The window 5 is tiltably mounted about a first tilting axis 7 and a second tilting axis 8, which are perpendicular to each other and in at least one state of the infrared imaging assembly 1 define a plane that runs perpendicular to the beam axis 6. According to the embodiment shown in Figure 1, the window is made of a material that comprises Germanium. Alternatively, the material may also comprise Silicon or Gallium Arsenide or may essentially consist of Germanium or Silicon Gallium Arsenide. Moreover, the window 5 has a transparency of more than 80 percent in a wavelength range between 8 to 14 pm. Alternatively, the window 5 may have a transparency of more than 95 percent in a wavelength range between 0.75 and 14 pm. The refractive index of the window is more than 1.6.

[0091] Moreover, the window 5 comprises a first optical surface 10 and a second optical surface 11 , which face away from each other. Both surfaces are coated with an anti-reflection coating, which is configured to have a reflectivity of less than 20 percent, may however be less than 5 percent for a wavelength range between 8 to 14 pm or 0.75 to 2.5 pm or 2 to 6 pm.

[0092] The window 5 has a width 12, a thickness 13 and is arranged in a distance 14 from the image sensor 2. The thickness 13 is 2.5 mm, may however be up to 5 mm.

[0093] As is shown in view b) of Figure 1, by tilting the window 5 about the first axis 7, the infrared beam is deflected by a shift Ay. The dimensions 12, 13 and 14 of chosen such that the shift Ay of the infrared beam 9 corresponds to a fraction of the pixel size, here 0.5 of the pixel size.

[0094] A tilt of the window 5 may be performed about the first tilting axis 7 and the second tilting axis 8, such that the shift Ay may not only be performed parallel to the image plane of Figure 1 but also perpendicular to the image plane of Figure 1.

[0095] As described in detail with respect to Figures 2 to 5, the infrared imaging assembly 1 comprises an operation state, in which the window 5 is at rest and the image sensor 2 is in a state of imaging. In other words, the infrared imaging assembly 1 is operated in discrete operation mode, wherein the image sensor generates one or more images within a rest state of the window 5. As also described in detail with respect to Figures 2 to 5, the infrared imaging assembly 1 comprises an actuator, which is designed to tilt the window 5 about the first tilting axis 7 and / or the second tilting axis 8 between at least two tilted positions with a cycle frequency of 5 to 50 Hertz.

[0096] Figure 2 shows a shifting unit 4, which comprises the window 5 and which is designed in order to enable a window movement according to the description of Figure 1.

[0097] The shifting unit 4 comprises a base 15, which is designed as a printed circuit board (PCB) that on the one hand provides a mechanical stability for the shifting unit 4 and on the other hand holds and connects electrical components to each other, which are necessary to operate the shifting unit. Moreover, the shifting unit 4 comprises a frame 16 which holds the window 5 and which is mounted by means of spring elements 17 to the base 15. The spring elements are designed and arranged such that the window 5 can be tilted about the first tilting axis 7 and the second tilting axis 8 in accordance to Figure 1.

[0098] The shifting unit 4 also comprises four electromagnetic actuators, each comprising a coil 18 and a magnet (see Figure 3).

[0099] The coils 18 are designed as integral parts of the PCB and each are electrically connected to an electrical energy source (not shown). By providing an electrical current for the coils 18, a magnetic field is generated. The magnets are attached to the frame 16 such that the generation of a magnetic field of the coils 18 interacts with the magnetic field of the magnets. This causes a tilting motion of the frame 16 and the window 5 about the first tilting axis 7 and / or the second tilting axis 8.

[0100] The shifting unit 4 also comprises a control unit (not shown) which is connected to the electrical energy source and controls the tilting motion of the frame 16 and the window 5 as a function of the electrical current that passes through the coils 18.

[0101] Since the electric current that passes through the coils 18 causes heat, the shifting unit 4 may be arranged such that the frame 16 is arranged between the infrared image sensor and the base 15. Additionally or alternatively, a thermal insulation layer (not shown) may be provided between the coils 18 and the infrared image sensor.

[0102] Figure 3 shows the shifting unit 4 in another perspective view. The explanations regarding Figure 2 apply accordingly.

[0103] Figure 4 shows the shifting unit 4 in a side view. In addition to the explanations regarding Figures 2 and 3, a magnet 19 is visible, which is attached to the frame 16.

[0104] Figure 5 shows the shifting unit 4 in a top view. The explanations regarding Figures 2, 3 and 4 apply accordingly.

[0105] Figure 6 shows a shifting unit 4, which comprises the same components as the shifting units 4 described above in view of Figures 1 to 5. In this respect, the above explanations with regard to the achievable advantages apply accordingly. In contrast to the shifting units 4 according to Figures 1 to 5, shifting unit 4 as shown in Figure 6 is provided with a control unit 20, which is connected to four coils 18 by means electric connections 21. The coils 18 are each part of an electromagnetic actuator as described above, which at least partly enables a tilting motion about tilting axes 7 and 8. According to the embodiment shown in Figure 6, control unit 20 is configured as a microcontroller that provides electric energy to the coils 18 in a controlled manner to enable the desired motion in terms of tilting amplitudes and frequencies.

[0106] Control unit 20 also comprises a control element 22, which is configured as a switch by means of which the shifting unit 4 can be turned on and off. Additionally or alternatively, the switch may be configured to set two or more functional states of the shifting unit 4, which may differ in a motion amplitude or frequency. In particular, the functional state may be chosen depending on the properties of the infrared image sensor. In particular, by turning off the shifting unit 4, an object, which moves relative to the imaging assembly or at least its infrared sensor can be detected without undesirable blurring effects.

Claims

Claims1. Infrared imaging assembly (1) comprising an infrared beam shifting unit (4) and an infrared image sensor (2) comprising a plurality of pixels (3), wherein the infrared beam shifting unit (4) and the infrared image sensor (2) are located along a beam axis (6) and wherein the shifting unit (4) comprises a window (5), which is tiltably mounted about a first tilting axis (7), which lies within a plane of the window and wherein the window (5) is configured to shift an infrared beam (9) passing through the window (5) along the infrared beam axis (6) onto the image sensor by a fraction of a pixel (3) size and as a function of a tilt about the first tilting axis (7).

2. Infrared imaging assembly (1) according to claim 1, wherein the window (5) is designed to have a transparency of more than 80 percent preferably of more than 90 percent and in particular preferably more than 95 percent in a wavelength range between 8 to 14 pm.

3. Infrared imaging assembly (1) according to one of the preceding claims, wherein the window (5) is designed to have a transparency of more than 80 percent preferably of more than 90 percent and in particular preferably more than 95 percent in a wavelength range between 0.75 to 2.5 pm.

4. Infrared imaging assembly (1) according to claim 1, wherein the window (5) is designed to have a transparency of more than 80 percent preferably of more than 90 percent and in particular preferably more than 95 percent in the wavelength range between 2 to 6 pm.

5. Infrared imaging assembly (1) according to one of the preceding claims, wherein the window is made of a material that comprises Germanium or Silicon or Gallium Arsenide or which essentially consists of Germanium or Silicon Gallium Arsenide.

6. Infrared imaging assembly (1) according to one of the preceding claims, wherein the pixels (3) each have a size of 10 to 20 pm.

7. Infrared imaging assembly (1) according to one of the preceding claims, wherein the shifting unit (4) is configured to shift the infrared beam by 0.2 to 0.8 of the pixel size.

8. Infrared imaging assembly (1) according to one of the preceding claims, wherein the window (5) comprises a material with a refractive index of more than 1.6 and in particular more than 2.0 and preferably more than 3.0.

9. Infrared imaging assembly (1) according to one of the preceding claims, wherein the window comprises a first optical surface (10) and a second optical surface (11).

10. Infrared imaging assembly (1) according to claim 9, wherein the first optical surface (10) and the second optical surface (11) are at least 2.5 mm and in particular 3.0 mm and preferably 5 mm spaced apart from each other.

11. Infrared imaging assembly (1) according to claim 9 or 10, wherein the first surface (10) and / or the second surface (11) is coated with an anti-reflection coating, which is configured to have a reflectivity of less than 20 preferably less than 10 and most preferably less than 5 percent between 8 to 14 pm or 0.75 to 2.5 pm or 2 to 6 pm.

12. Infrared imaging assembly (1) according to one of the preceding claims, wherein the image sensor (2) comprises a pixel row and several additional pixel columns arranged at an angle of more than 45° and less than 135° with respect to a direction of the pixel row.

13. Infrared imaging assembly (1) according to claim 12, wherein the window (5) is tiltably mounted about a second tilting axis (8), which lies within the plane of the window (5) and the window (5) shifts infrared beam by a portion of a pixel (3) size at the angle of more than 45° and less than 135° with respect to the direction of the pixel row.

14. Infrared imaging assembly (1) according to one of the preceding claims, wherein the shifting unit (4) is configured to have a cycling frequency of 5 to 50 Hertz, preferably 10 to 40 Hertz.

15. Infrared imaging assembly (1) according to one of the preceding claims, wherein the shifting unit (4) comprises one operation state, in which the shifting unit (4) does not perform a time dependent shifting and the image sensor is in a state of imaging.

16. Infrared imaging assembly (1) at least according to claim 15, wherein the image sensor generates several images within a rest state of the shifting unit.

17. Infrared imaging assembly (1) according to one of the preceding claims, wherein the shifting unit comprises an actuator and in particular a control unit (20), which is configured to control the shifting unit (4), in particular by providing signals and / or electrical energy to the actuator and wherein the shifting unit (4) preferably further comprises a control element (22), which is connected to the control unit (20) at least by means of a signal connection and wherein the control element (22) in particular comprises at least a switch, which is configured to set the control unit (20) and / or the shifting unit (4) between at least two functional states, in particular to turn the shifting unit (4) on and off.

18. Infrared imaging assembly (1) according to one of the preceding claims, wherein the actuator is a magnetic force-based actuator, a shape memory alloyed based actuator, or a piezo based actuator.

19. Infrared imaging assembly (1) according to one of the preceding claims, wherein the shifting unit comprises a temperature sensor.

20. Infrared imaging assembly (1) according to one of the preceding claims comprises a thermal insulation, which is located between the shifting unit (4) and the image sensor (2).

21. Infrared imaging assembly (1) according to one of the preceding claims and claim 17, wherein the actuator is located on a side of the shifting unit (2) facing away from the image sensor.

22. Infrared imaging assembly (1) according to one of the preceding claims comprises a cooling system, which is thermally coupled to the shifting unit.

23. Infrared beam shifting unit (4), in particular for a infrared imaging assembly according to at least one of the claims 1 to 22, with a window (5), which is tiltably mounted about a first tilting axis (7), which lies within a plane of the window (5) and wherein the window (5) is configured to laterally shift an infrared beam (9) passing through the window (5) along an infrared beam axis (6) as a function of a tilt about the first tilting axis (7).

24. Infrared beam shifting unit (4) according to claim 23, with at least an actuator and a control unit (20), which is configured to control the shifting unit (4), in particular by providing signals and / or electrical energy to the actuator and wherein shifting unit further comprises a control element (22), which is connected to the control unit (20) at least by means of a signal connection.

25. Infrared beam shifting unit (4) according to claim 23 or 24, wherein the control element (22) comprises at least a switch, which is configured to set the control unit (20) and / or the infrared beam shifting unit (4) between at least two functional states, in particular to turn the shifting unit on and off.

Images