Optical sensor

Abstract

The invention relates to an optical sensor (1) comprising a housing (2) in which at least one sensor component for detecting an object and electronic components are arranged. The at least one electronic component generates an output signal as a function of the sensor signal of the sensor component. A section of the housing (2) made of a heat-conducting material is connected to the electronic component and / or the sensor component by means of a heat-conducting layer (15) such that heat generated therein is conducted outwards by means of the housing (2).

Description

TECHNICAL FIELD

[0001] The invention relates to an optical sensor. BACKGROUND

[0002] Such optical sensors are generally used for detecting objects. To this end, the optical sensor integrates sensor components and electronic components in a housing.

[0003] As sensor components, the optical sensor generally has an emission unit which emits a light beam and a reception unit which receives the light beam reflected back by an object.

[0004] At least one of the electronic components constitutes an evaluation unit in which an output signal is generated from the sensor signals of the sensor components.

[0005] The optical sensor can be used for detecting objects in a monitored region. In this case, the optical sensor generates an object-determination signal as an output signal which indicates whether an object is present in the monitored region.

[0006] In particular, the optical sensor can also be used for detecting a code, such as a bar code or a two-dimensional code, i.e. the optical sensor forms a code reader. In this case, code information contained in the sensor signals of the reception unit is decoded in the evaluation unit, so that the detected code is output as an output signal.

[0007] In particular in embodiments in the form of a code reader, the reception unit is designed in the form of an image sensor, i.e. an imager. The image sensor is advantageously equipped with an emission unit in the form of an illumination unit, which has, for example, a multiple arrangement of light-emitting diodes.

[0008] The image sensor is advantageously connected to a computer unit which constitutes the evaluation unit via a MIPI line. The MIPI line is a serial interface line which is standardized by the MIPI Alliance and which has a high data transmission rate and is fast.

[0009] The problem here is that such MIPI lines are susceptible to interference when they are relatively long.

[0010] A further general problem of optical sensors is that their internal space is heated by the heating power of the electronic components and the sensor components, which can lead to impaired or even failed functioning of the optical sensor. SUMMARY

[0011] It is the task of the invention to design an optical sensor of the type described above which is less susceptible to interference.

[0012] To solve the stated task, the features according to the preferred technical solution are provided. Advantageous embodiments of the invention and useful extensions are described in the alternative technical solutions.

[0013] The application relates to an optical sensor comprising a housing in which at least one sensor component for detecting an object and an electronic component are arranged. At least one electronic component generates an output signal from a sensor signal of the sensor component. A section of the housing made of a thermally conductive material is connected to the electronic component and / or the sensor component by means of a thermally conductive layer, so that heat generated therein is conducted outwards through the housing.

[0014] A significant advantage of the application is that the heat generated in the interior space as a result of the heating power of the sensor component and the electronic component can be effectively dissipated outwards, i.e. into the environment of the optical sensor. This prevents the electronic component and the sensor component from overheating, so that the optical sensor is protected from malfunctioning or even failure. This effect can be further enhanced if the housing is coated on the outside with a heat-dissipating paint.

[0015] An important aspect of the application is that the housing is made entirely or at least partially of a thermally conductive material, i.e. a material having a high thermal conductivity. Thus, heat can be conducted outwards through the thermal conductivity of the optical sensor housing.

[0016] Another important aspect of the application is that the housing structure of the optical sensor housing is designed in such a way that the individual housing sections are in direct contact with the electronic component and / or the sensor component and are connected to these components by means of thin thermally conductive layers. In this way, the heat of the electronic component or the sensor component can be directly transferred to the housing sections and from there to the entire housing via the thermally conductive layers, so that the heat generated in the region of the electronic component or the sensor component is directly dissipated.

[0017] One or more housing sections of the housing can project from the inside of the housing wall and lead directly to the electronic component or the sensor component therefrom.

[0018] It is particularly advantageous if the housing is made of a thermally conductive metallic material.

[0019] Metallic materials have a very high thermal conductivity and are therefore particularly suitable for dissipating heat from the interior of the housing.

[0020] According to an advantageous design, the metallic material is a zinc die casting or an aluminum die casting.

[0021] Housings made of zinc die castings or aluminum die castings can be produced efficiently or reasonably. Furthermore, it is also advantageous that complex housing geometries can be realized.

[0022] The thickness of the thermally conductive layer is generally low, preferably in the micrometer range. This ensures that the housing structure has good thermal conduction properties.

[0023] It is advantageous if a thermally conductive pad or a thermally conductive paste is provided as the thermally conductive layer.

[0024] The printed circuit board, as a large and flat component, generates a large amount of heat during the operation of the optical sensor, in particular due to other electronic components present on the printed circuit board.

[0025] By directly connecting the printed circuit board to the housing cover or housing wall via a thermally conductive layer having a thermal conductivity, the heat generated in the area of the printed circuit board can be effectively conducted out of the interior of the housing.

[0026] In general, the surface of the printed circuit board itself or of other electronic components placed on the printed circuit board can be directly connected to the thermally conductive layer.

[0027] According to another advantageous embodiment, the cooling body made of thermally conductive material is an integral part of the housing, the cooling body opening onto the inner side of the housing wall made of thermally conductive material, that is to say, the cooling body is formed integrally with the housing body of the housing, which forms an enclosure for the sensor components and electronic components. Alternatively, the cooling body can also be connected to the housing body in a thermally conductive manner, for example by screw connections. The cooling body is in contact with at least one electronic component via at least one thermally conductive layer.

[0028] In particular, the cooling body is in contact with the upper side of the printed circuit board via at least one thermally conductive layer.

[0029] The cooling body, as a part of the housing, is optimized in terms of its geometry such that it can be directly connected to the sensor components, in particular the printed circuit board, of the electronic components to be cooled, so that the heat can be directly dissipated via the cooling body and conducted outwards via the housing wall.

[0030] To this end, the cooling body has a sufficiently large surface area, so that a large amount of heat can be conducted out with it.

[0031] In this case, the thermally conductive layer can also be in direct contact with the surface of the printed circuit board or other electronic components placed thereon.

[0032] According to an advantageous embodiment, the optical sensor has an image sensor and a lens as sensor components.

[0033] For example, the image sensor, that is to say the imager, can consist of a matrix CMOS or CCD array, while the lens consists of a lens assembly in a known manner.

[0034] In this case, the optical sensor can be designed as a code reader with which bar codes and two-dimensional codes can be detected.

[0035] Advantageously, the image sensor and the lens are mounted on the upper side of the printed circuit board.

[0036] Advantageously, the cooling body has cooling ribs which radially lead to the lens around the image sensor.

[0037] Here, the lens and the image sensor are mounted in a tube which is positionally fixed by means of cooling ribs.

[0038] The cooling body with cooling ribs thus has a dual function, it serves not only for heat dissipation but also for positionally fixing the lens and the image sensor.

[0039] The tube is connected to the cooling ribs by means of a clamping connection and a screw connection, as desired.

[0040] Both solutions ensure reliable position fixing of the tube.

[0041] According to an advantageous design, the cooling body has a centering pin which can be inserted into a hole in the printed circuit board.

[0042] Here, the image sensor and the lens are positioned relative to the hole in the printed circuit board by means of the centering pin, the hole constituting a camera receptacle.

[0043] The hole is machined in the printed circuit board in advance, in particular with the aid of image processing, in the intended position, so that a high-precision positioning of the image sensor in the camera receptacle can be ensured by subsequent insertion of the centering pin.

[0044] According to an alternative design, a sensor component in the form of a light-emitting diode is mounted on the upper side of the printed circuit board, the light-emitting diode forming an illumination unit.

[0045] The illumination unit and the image sensor with lens are thus mounted on the same side of the circuit board, preferably directly adjacent. The light beam emitted by the light-emitting diode can illuminate the field of view of the image sensor.

[0046] Advantageously, the light-emitting diode is located in a recess of the cooling rib.

[0047] The recess of the cooling body has an aperture function and prevents crosstalk, i.e. the light beam of the light-emitting diode directly impinges on the lens and the image sensor.

[0048] In addition, the cooling body has additional functions, for example the cooling body carries a lens plate for beam shaping of the light beam emitted by the light-emitting diode.

[0049] According to an advantageous embodiment, a computer unit which forms an electronic component is mounted on the lower side, the computer unit forming an evaluation unit in which the output signal is generated. The computer unit and the image sensor are arranged in an opposing manner on both sides of the printed circuit board.

[0050] In particular, the computer unit is a microcontroller.

[0051] The positioning of the computer unit on the lower side of the circuit board and the positioning of the image sensor on the upper side are optimally adapted to one another, so that the image sensor can be connected to the computer unit by means of a very short cable.

[0052] This is particularly advantageous if the computer unit and the image sensor are connected by means of MIPI lines.

[0053] Since the MIPI lines can be very short, unwanted interference can be avoided when data is transmitted by means of these MIPI lines. BRIEF DESCRIPTION OF DRAWINGS

[0054] The application will be explained below with reference to the drawings. In the drawings:

[0055] Figure 1 : shows an embodiment of an optical sensor according to the application.

[0056] Figure 2 : shows Figure 1 a separate view of the components of the optical sensor shown.

[0057] Figure 3 : shows Figure 1 a sectional view of the optical sensor shown. DETAILED DESCRIPTION

[0058] Figure 1 An embodiment of an optical sensor 1 according to the application is shown. Figure 2 Components of the optical sensor are shown. Figure 3 A schematic sectional view of the optical sensor 1 along the height of the narrow side of the optical sensor 1 is shown, not to scale.

[0059] In the present case, the optical sensor 1 is designed as a code reader with which bar codes and two-dimensional codes can be detected and decoded.

[0060] The optical sensor 1 has a housing 2 in which the electronic components and sensor components of the optical sensor 1 are integrated. The housing 2 is made of a material with high thermal conductivity. To this end, the housing 2 is made of a metal material, for example. In the present case, the housing 2 consists of two zinc or aluminum die cast parts, namely a housing body 2a and a housing cover 2b which closes an opening on the lower side of the housing body 2a.

[0061] A plug cover 3 with electrical connections 4 is fixed on the side of the housing body 2a. The plug cover 3 can also be made of a zinc or aluminum die cast part.

[0062] A printed circuit board 5 as central electronic component is fixed on the inner side of a housing wall 6 of the housing 2.

[0063] The image sensor 7 and the lens 8 assigned to the image sensor are mounted as sensor components on the upper side of the printed circuit board 5. The lens 8 is mounted in a tube 9, which is fixed on the upper side of the printed circuit board 5. The tube 9 is composed of a light- impermeable material and is open on its upper side.

[0064] The image sensor 7 is preferably composed of a matrix CCD or CMOS array. The lens 8 is composed of a lens assembly.

[0065] Furthermore, a light-emitting diode 10, which constitutes an illumination unit, is mounted on the upper side of the printed circuit board 5. The field of view of the image sensor 7 is illuminated by the light beam of the illumination unit.

[0066] The light-emitting diode 10 is assigned a lens plate 11 with lens elements 12, by means of which the beam shaping of the light beam takes place.

[0067] In the opening on the upper side of the housing 2, a window 13, which is transparent to the light beam, is placed.

[0068] On the lower side of the printed circuit board 5, a microcontroller 14 is mounted, which constitutes a computer unit and thus also an electronic component of the optical sensor 1. Instead of the microcontroller 14, another processor can also be used. The microcontroller 14 is located directly opposite the image sensor 7. The image sensor 7 is connected to the microcontroller 14 by means of MIPI lines, which are not shown. The sensor signals of the image sensor 7 are read into the microcontroller 14 by means of the MIPI lines, which constitutes an evaluation unit for analyzing the sensor signals.

[0069] For detecting a code, the light beam of the light-emitting diode 10 is guided from the optical sensor 1 through the window 13 into the detection area. The light beam reflected by the code is guided through the pane or window glass and the lens 8 to the image sensor 7. The sensor signals generated in the image sensor 7, which contain the code information of the code, are evaluated in the microcontroller 14 in order to decode the code. The decoded code is output as an output signal by the optical sensor.

[0070] According to the application, the housing 2, which is composed of a thermally conductive material, serves to dissipate heat from the interior of the optical sensor 1.

[0071] To this end, the individual sections of the housing 2 are connected directly, i.e. without an intermediate air gap, to the electronic components or sensor components by means of thermally conductive layers 15, so that the heat generated there is dissipated by means of the thermally conductive layers 15 and the housing 2 and guided to the outside, i.e. to the environment of the optical sensor 1.

[0072] The layer thickness of the thermally conductive layers 15 is in the micrometer range and can be composed of thermally conductive pads or thermally conductive paste.

[0073] In this case, the heat generated in the printed circuit board 5 or the microcontroller 14 is conducted away to the outside via the thermally conductive layer 15 on the underside of the printed circuit board 5 or the microcontroller 14, which is in direct contact with the housing cover 2b, and the housing cover 2b, which is in contact with the thermally conductive layer 15.

[0074] Furthermore, a cooling body 16 is provided, which terminates on the inside of the housing wall 6, is formed integrally with the housing wall 6 and is an integral part of the housing body 2a. Alternatively, the cooling body 16 can be connected to the housing body 2a in a thermally conductive manner.

[0075] The cooling body 16 extends in a plane perpendicular to the housing wall 6 and terminates on the housing wall. The cooling body 16 is dimensioned such that it supports the printed circuit board 5 in a planar manner, with a further thermally conductive layer 15 being present between the printed circuit board 5 and the cooling body 16. Thus, the heat generated in the region of the printed circuit board 5 can be conducted directly outward via the thermally conductive layer 15, the cooling body 16 and the housing wall 6.

[0076] The cooling body 16 has cooling ribs 17, which extend radially toward the tube 9. The cooling ribs 17 serve to positionally fix the tube 9, which is fixed on the cooling ribs 17 by means of a clamping connection. Alternatively, the cooling body 16 can form an annular segment with an internal thread, into which the tube 9 is screwed.

[0077] It can be seen in particular from Figure 3 that the cooling body 16 has a recess 18, in which the light emitting diode 10 is mounted. A further thermally conductive layer 15, which is not shown, can also be present in the region of the recess 18 and provides a thermally conductive connection between the light emitting diode 10 and the cooling body 16.

[0078] According to an advantageous development, the cooling body 16 can have a centering pin, which can be inserted into a hole of the printed circuit board 5.

[0079] Here, the image sensor 7 is positioned with respect to the lens 8 and the hole of the printed circuit board 5, which forms a camera receptacle, by means of the centering pin.

[0080] The centering pin and the hole are not shown in the figures.

[0081] List of reference signs:

[0082] (1) optical sensor

[0083] (2) housing

[0084] (2a) housing body

[0085] (2b) housing cover

[0086] (3) plug cover

[0087] (4) joint

[0088] (5) printed circuit board

[0089] (6) housing wall

[0090] (7) image sensor

[0091] (8) lens

[0092] (9) tube

[0093] (10) light emitting diode

[0094] (11) lens plate

[0095] (12) lens element

[0096] (13) window

[0097] (14) microcontroller

[0098] (15) thermally conductive layer

[0099] (16) cooling body

[0100] (17) cooling rib

[0101] (18) recess

Claims

1. An optical sensor (1) comprising a housing (2) in which at least one sensor component for detecting an object and an electronic component are arranged, wherein the at least one electronic component generates an output signal based on a sensor signal of the sensor component, characterized in that The section of the housing (2) made of heat-conducting material is connected to the electronic component and / or sensor component via a heat-conducting layer (15), so that the heat generated therein is dissipated to the outside through the housing (2).

2. The optical sensor (1) according to claim 1, characterized in that The housing (2) is made of a heat-conducting metal material; and / or a heat-conducting pad or heat-conducting paste is provided as a heat-conducting layer (15).

3. The optical sensor (1) according to claim 2, characterized in that The metal material is a zinc die casting or an aluminum die casting.

4. The optical sensor (1) according to any one of claims 1 to 3, characterized in that A printed circuit board (5) is provided as an electronic component, the bottom side of which is connected via at least one heat-conducting layer (15) to a housing cover (2b) made of a heat-conducting material or to a housing wall (6) made of a heat-conducting material.

5. The optical sensor (1) according to any one of claims 1 to 4, characterized in that A cooling body (16) extends through the inner side of a housing wall section made of a heat-conducting material, the cooling body being made of a heat-conducting material and being a component of the housing (2) or being connected to the housing in a heat-conducting manner; and the cooling body (16) is in contact with at least one electronic component via at least one heat-conducting layer (15).

6. The optical sensor (1) according to claim 4, characterized in that The cooling body (16) is in contact with the top side of the printed circuit board (5) via at least one heat-conducting layer (15).

7. The optical sensor (1) according to any one of claims 1 to 6, characterized in that An image sensor (7) and a lens (8) are present as sensor components.

8. The optical sensor (1) according to claim 7, characterized in that The image sensor (7) and the lens (8) are mounted on the upper side of a printed circuit board (5); and / or the lens (8) and the image sensor (7) are mounted in a tube (9), which is fixed in position by means of cooling ribs (17).

9. The optical sensor (1) according to claim 7 or 8, characterized in that The cooling body (16) has cooling ribs (17) which extend radially toward the lens (8) surrounding the image sensor (7); and / or the tube (9) is connected to the cooling ribs (17) of the cooling body by a clamping connection or a screw connection.

10. The optical sensor (1) according to claim 4, characterized in that The cooling body (16) has a centering pin which can be inserted into a hole in the printed circuit board (5), wherein the image sensor (7) and the lens (8) are positioned relative to the hole in the printed circuit board (5) by means of the centering pin, the hole forming the camera receptacle.

11. The optical sensor (1) according to claim 4 and 5, characterized in that A light emitting diode (10) forming a sensor component and emitting a light beam is mounted on the upper side of the printed circuit board (5), the light emitting diode forming a lighting unit, wherein the light emitting diode (10) is located in a groove (18) of the cooling rib (17).

12. The optical sensor (1) according to any one of claims 4 to 11, characterized in that A computer unit forming the electronic component is mounted on the underside of the printed circuit board (5), said computer unit forming an evaluation unit in which output signals are generated.

13. The optical sensor (1) according to claim 12, characterized in that The computer unit and the image sensor (7) are connected via a MIPI line.

14. The optical sensor (1) according to any one of claims 1 to 13, characterized in that The outer side of the shell is coated with heat dissipation paint.

15. The optical sensor (1) according to any one of claims 1 to 14, characterized in that The optical sensor is a code reader.

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