Lamp with liquid detection function

Abstract

The present application relates to a luminaire comprising a compartment containing at least one light source, the at least one light source configured to emit light in a main light emission direction. A lens is provided which is movably arranged relative to the light source in a direction of the main light emission direction, and an electric motor is configured to move the lens relative to the light source in the main light emission direction. A control unit determines a current used by the electric motor to move the lens in the main light emission direction, wherein the control unit is configured to detect the presence of a liquid on the lens based on the determined current.

Description

Technical Field

[0001] This application relates generally to luminaires, and more specifically to techniques for protecting luminaires from moisture or liquids. Background Technology

[0002] In many industrial lighting applications, entry protection is used to enhance robustness against water and particulate matter such as dust. This typically leads to increased cost and / or complexity, reduced maintainability, etc. When applying protection to joints between components arranged to accommodate mutual movement, solutions often involve special seals and hydrophobic greases, which have the disadvantages of higher friction and noise, and / or, alternatively, lower lighting quality.

[0003] In recreational and architectural lighting, luminaires (such as moving head lights) are typically used outdoors, exposed to the risk of rain showers and / or other sources of moisture. Therefore, the product should be safely placed under a roof or protected with an IP rating of 44 or higher. A crucial aspect of moving head lights is the movement of the lens relative to the light source positioned within the head. Traditionally, an additional window is placed at a certain distance in front of the lens to allow the lens to move relative to the light source without colliding with it. The window protects the lens and reduces the risk of moisture entering the head. However, the window can cause internal reflections, and fingerprints on the window can alter the output light. The window itself can further reduce the output from the light source and increase the weight of the moving head light. Therefore, there is a need to overcome the aforementioned problems and provide a luminaire with high light output and minimal internal reflections, even when used outdoors exposed to rain or in environments where other objects may be present on the lens that is not protected by closed windows. Summary of the Invention

[0004] The features of the independent claims satisfy this need. Further aspects are described in the dependent claims.

[0005] According to one aspect, a luminaire is provided, the luminaire including a compartment configured to accommodate at least one light source configured to emit light in a principal light emission direction. Furthermore, a lens movably arranged relative to the light source in the principal light emission direction is provided, and an electric motor is configured to move the lens relative to the light source in the principal light emission direction. The luminaire also includes a control unit configured to determine a current used by the electric motor to move the lens in the principal light emission direction, and the control unit is configured to detect the presence of liquid on the lens based on the determined current.

[0006] At least one technical advantage of the disclosed technology over the prior art is that, using the luminaires discussed above or further detailed below, it is easy to determine whether an unintended object (such as a liquid) present on the lens is part of the mass being moved by the motor. When an electric motor that moves the lens relative to the light source in the main light emission direction pulls a larger-than-expected current, it can be inferred that there is a liquid or any other object with a certain mass and weight on the lens. Besides the presence of a liquid, any other object may adhere to the lens, and this object or liquid may degrade the light output in the main light emission direction and may cause unintended internal reflections. Attached Figure Description

[0007] To gain a more detailed understanding of the above-described features of the various embodiments, a more specific description of the inventive concept briefly outlined above can be given with reference to the various embodiments, some of which are illustrated in the accompanying drawings. It should be understood that the drawings illustrate only typical embodiments of the inventive concept and should therefore not be construed as limiting the scope in any way. The invention will now be described in more detail with reference to the accompanying drawings, wherein the same reference numerals refer to the same elements.

[0008] Figure 1 A cross-sectional view through a luminaire is shown, the luminaire being configured to detect the presence of liquid on the lens when the lens is in a first position.

[0009] Figure 2 A cross-sectional view through the luminaire is shown, with the lens moved to a second, more extended position.

[0010] Figure 3 A cross-sectional view through the luminaire is shown, in which the lens is positioned such that liquid exists in front of the lens.

[0011] Figure 4 It shows Figures 1 to 3 A cross-sectional view of the luminaire, positioned to allow for the removal of liquid present on the lens.

[0012] Figure 5 An example representation of a flowchart showing how a luminaire determines whether a liquid may be present on the lens is shown. Detailed Implementation

[0013] In the following description, embodiments of the invention will be illustrated in detail with reference to the accompanying drawings. It should be understood that the following description of the embodiments is not intended to be limiting. The scope of the invention is not intended to be limited by the embodiments or drawings described below, which are merely illustrative.

[0014] The accompanying drawings should be considered schematic, and the elements shown are not necessarily to scale. Rather, the various elements are shown such that their function and general purpose will be obvious to those skilled in the art. Any connection or coupling between functional blocks, devices, or components of the physical or functional units shown in the drawings and described below may also be achieved through indirect connections or couplings. Coupling between components may be established via wired or wireless connections. Functional blocks may be implemented in hardware, software, firmware, or a combination thereof.

[0015] Figure 1 and Figure 2 A lamp 100 in the form of a moving head lamp is shown according to various embodiments. Figure 1 and Figure 2 A cross-sectional view is shown. The luminaire 100 includes, but is not limited to, a head 102, a yoke 103, and a base 104. Two first connectors 121, 122 are arranged between the head 102 and the yoke 103, and a second connector 131 is arranged between the base 104 and the yoke 103, such that the head 102 is rotatably connected to the yoke 103 and the yoke 103 is rotatably connected to the base 104. Figures 1 to 3 As shown, the luminaire (here, head 102) includes a compartment 140 that houses one or more light sources 110. At least one light source is positioned along... Figure 2 The light emitted is in the main light emission direction indicated by the middle arrow A, where arrow A is parallel to the central axis 113 of the head.

[0016] Figure 1 and Figure 2 A cross-sectional view of the luminaire 100 is shown. A lens 107 is movably arranged relative to a light source 110. The lens 107 is arranged substantially perpendicular to at least one light source 110, and the movement of the lens 107 relative to the light source 110 is a substantially linear movement in a direction away from or toward at least one light source 110, as indicated by arrow B. The lens may be a single lens, but lens 107 may also be a group of lenses. Thus, the lens moves in the main light emission direction and is positioned substantially perpendicular to the main light emission direction. The movement of the lens 107 adapts to the shape of the light beam 150 emitted by the luminaire in the main light emission direction.

[0017] A deformable corrugated tube or membrane 111 with a tubular shape extends from a first end 118 to a second end 119, and forms an inner cavity or recess 120 at the front end of the luminaire from which the light beam exits the luminaire. The membrane 111 is attached to a lens 114 at the first end 118 and to the upper part of a sidewall 125 of the head 102 at the second end 119. The sidewall 125 extends circumferentially around the lens 114, and the lens 114 is movable relative to the sidewall 125. Figure 2 In the middle, the deformable membrane 111 is in a compressed configuration, while Figure 1 In the middle, the deformable membrane 111 is in an extended configuration.

[0018] Because the membrane 111 is attached to the lens 107 at the first end 118, the lens 114 closes the head 102 at the end where the light leaves the luminaire, and allows light beams from at least one light source 110 to pass unobstructed in the main light emission direction. Figures 1 to 3 In the case shown, the main light emission direction is vertical, but it is clear that the main light emission direction depends on the orientation of the head 102 relative to the yoke which can rotate about the axis x, i.e., tilt rotation, and the orientation of the yoke 103 relative to the base 104, i.e., translational (pan) rotation.

[0019] When the lens 107 is moved relative to at least one light source 110, the membrane 111 is compressed and expanded as the lens 107 moves, since the membrane 111 is attached to the lens 107 at a first end 118 and to the sidewall 125 of the head at a second end 119. The lens 107 is moved back and forth in front of the light source 110 using multiple motors 108, of which only two motors are visible. In the illustrated embodiment, the motors 108 are linear motors in the form of spindle motors. Other concepts, such as gears on a linear guide or conveyor belt drive, may also be used. The two visible motors 108 are arranged opposite each other relative to a central axis Y extending through the center of the light source to facilitate the linear movement of the lens 107.

[0020] By attaching the membrane 111 to the lens 107 at the first end 118 and to the sidewall 125 at the second end, an opening (not shown) can be sealed along the outer periphery of the lens 114, thereby preventing dust, particles, moisture or liquids and / or contaminants from entering the first compartment 140 along this periphery. Therefore, the use of an additional sealing window, which in conventional luminaires is typically located in front of the lens 114 at a distance from it, such as near the free end or recess of the sidewall 125, can be avoided.

[0021] Two motors 105 and 106 are arranged for the movement of the head 101. Motor 106 rotates the yoke relative to the base 104, and thus also rotates the head 102, while motor 105 tilts the head 102.

[0022] An external computer 200 communicates with a control unit 112 integrated in the base 104. The control unit 112 is arranged to control the movement of the lens 107, control at least one light source 110, control the movement of the head 102, control the movement of the yoke 103, etc.

[0023] The base 104 may also include user input elements (not shown) through which the user of the luminaire can control the luminaire. The user input elements may include one or more buttons, one or more touchpads, a keyboard, etc. Furthermore, the base 104 may include an orientation sensor 116 capable of determining the orientation of the base, yoke, and head in space, particularly relative to the vertical axis and relative to the Earth; in the illustrated case, the vertical axis corresponds to the Y-axis.

[0024] Such as combination Figure 1 and Figure 2 As discussed, when light generated by light source 110 exits the luminaire 100 due to a recess 120 corresponding to a cavity or barrel portion not enclosed by a transparent window, lens 107 is the last element in the optical path. No protective cover is provided at the height of the upper end of sidewall 125, thus creating a smaller or larger recess or cavity 120 at the front end of the light source, from which light exits the luminaire, depending on the position of lens 107. (As in conjunction with...) Figure 3 As shown, when the concave portion and the main light emission direction are relative to the vertical axis ( Figure 3 When the tilt angle is at a certain angle to the axis Y in the middle, liquid 300 from rainwater 301 may collect in the recess 120. Therefore, the tilt angle determines and affects whether and how much liquid 300 is collected in the recess 120 when there is rainwater. To determine whether there is liquid or any other object on the lens 107, the motor 108 can be monitored during operation. Since the weight of the lens 107 or any other component that the motor needs to move can be predetermined, the current required by the motor 108 to move the lens away from the light source 110 can be determined. Therefore, when the current pulled by the motor 108 is higher than expected, exceeding a defined threshold, it can be concluded that an unexpected object needs to be moved in addition to the lens 107. The control unit 112 or control unit 109, which can be implemented as a microcontroller, can monitor the motor in the closed-loop circuit during operation, and when the current required by the motor 108 or the power consumed by the motor 108 to move the lens 107 away from the light source 110 exceeds a threshold, the control unit can conclude that there is liquid or any other object in the recess 120. Obviously, as Figure 3 The liquid 300 shown will negatively affect the emitted beam and may degrade the components involved. Therefore, when the presence of liquid is detected, the control unit can decide to drain the liquid from the recess 120. (As shown in the diagram...) Figure 4 As shown, this can be achieved by moving the lamp, by controlling the tilt angle and / or translation angle of the head 102, so that the liquid can be removed from the recess 120 under the action of gravity.

[0025] An external computer or lighting control console communicates with control unit 112, and control unit communicates directly with motor 108 or via control unit 112, which may be part of a drive circuit board. Typically, the necessary calculations required to determine the presence of liquid on lens 107 can be performed by one of control units 109 and 112, or can be performed in part by one of control units 109 and 112 and in part by the other, based on information from both control units 109 and 112.

[0026] Control unit 109 or 112 can use different information to determine whether liquid or any other object is present on lens 107. Lens 107 can be moved using only the current or power supplied by motor 108. Furthermore, given the orientation of the recess relative to the vertical axis, control unit 109 or 112 can additionally use information from orientation sensor 116 to determine whether an object might be present on the lens. This may depend particularly on the tilt angle of head 102. For example, when the head is pointed horizontally, such that the main light emission direction is parallel to the horizontal plane (relative to the Earth), or when the main light emission direction is pointed at an angle greater than 90 degrees relative to the vertical axis, it can be concluded that no liquid or object can be present in recess 120 because, based on the orientation of the head, the liquid or object may have fallen. Therefore, control unit 112 may only detect the presence of liquid in the recess if the tilt angle relative to the vertical axis is below a certain threshold angle (such as 90 degrees) as a possible threshold angle; however, it should be understood that other threshold angles, larger or smaller, may be used depending on the environment and weather conditions of the luminaire installation. The orientation sensor 116 can be placed in the head 102 or the base 104. If the orientation sensor is located in the head 102, no information about translation or tilt values ​​is needed. However, when the orientation sensor is placed in the base 104 as shown, the correlation between orientation and translation and tilt values ​​is needed to determine whether a portion of the recess is positioned to allow liquid to be collected in the recess.

[0027] The control unit 112 can also use information from the liquid or rain sensor 115 present in the luminaire 100, which can actually detect the presence of liquid at the luminaire. A rain sensor alone can detect the presence of rain, but rain may only be present on the sensor and not on the lens, and the amount of liquid present on the lens 107 cannot be easily determined by the rain sensor alone. Furthermore, the rain sensor can be placed anywhere on the luminaire, where rain is likely to be detected independently of the luminaire's orientation. Therefore, a rain sensor alone will have difficulty detecting information other than dryness or wetness and whether liquid is actually present on the lens 107. Therefore, the control unit can determine the presence of liquid at the recess 120 based solely on the monitored current or power used by the motor 108, but can also use additional information, including information from the orientation sensor 116 and / or the rain sensor 115.

[0028] Figure 5 The diagram illustrates a possible implementation of a method by which the state diagram or control unit 112 determines the presence of liquid on lens 107. The method can begin at step or state 210, where the control unit begins monitoring for the presence of liquid. In step 220, the load on motor 108 is monitored, and it is determined whether the load is within a predetermined load range or whether the load is higher than expected, i.e., above a threshold. If this is not the case, the system returns to step 210 and continues monitoring. However, if an abnormal load is determined in step 220, the position of the lens and the orientation of the lamp and the head-mounted lamp can be determined (step 230). For this determination in step 230, determined translation and tilt values ​​of the head-mounted lamp can be used in step 232, particularly when the orientation sensor is placed in base 104. Furthermore, in step 234, the orientation of base 104 relative to the earth, the mounting method of lamp 100, and whether the base is horizontal or vertical and facing upwards or downwards can be determined. Based on the orientation, whether the base is horizontally or vertically aligned, or at any other angle relative to the horizontal axis, and based on translation and tilt values, it can be precisely determined whether the recess 120 is at least partially oriented towards the direction in which rainwater or liquid is expected to be collected in the recess, thereby retaining the rainwater or liquid in the recess 120. If it is determined in step 230 that the opening angle of the recess is at least partially upward (as determined in step 240), a mechanism can be initiated in step 250 by which liquid is removed from the recess under the influence of gravity (e.g., Figure 4As shown), the head is positioned facing downwards towards the Earth (step 250). The removal step can be initiated directly after confirmation or after a certain period of time. After the liquid removal step is completed, the control unit can return to start 210 and monitor, and the lamp can return to the position before the water removal process was initiated. If it is determined in step 240 that the recess is facing a direction in which liquid is unlikely to exist in the recess due to current gravity, the control unit can still increase the activation current in step 260 and set an alarm to inform the user of the lamp 100 that any other error may have occurred.

[0029] Some general conclusions can be drawn from the above, which will be discussed in more detail below. When the current required by the motor exceeds a predetermined threshold, the control unit 112 can detect the presence of liquid on the lens 107.

[0030] The luminaire may include a movable head, in which a lens, a light source, and an electric motor are located, and a control unit may be configured to initiate movement of the head when the presence of liquid is detected, so that the liquid is removed from the lens under gravity. (As in combination) Figure 4 The discussion likely involves setting the head to a defined tilt angle and / or translation angle, which allows the recess to be emptied under gravity alone.

[0031] Lens 107 can be an outer lens, having a lower surface facing the compartment containing the light source and an upper surface facing the space outside the luminaire, wherein the control unit is configured to detect the presence of liquid on the upper surface. Therefore, the lens is the outermost component of the luminaire, through which light passes when emitted along the main light emission direction.

[0032] The luminaire may also include an orientation sensor, such as sensor 116, configured to determine the vertical angle in space of the main light emission direction relative to the vertical direction on Earth, wherein the control unit may be configured to take into account the determined vertical angle to detect the presence of liquid on the lens. As discussed above, this may mean that liquid is likely to accumulate in the recess only when the vertical angle is within a defined range, such as + / - 90 degrees, and the control unit may only take countermeasures to expel the liquid by moving the head to the correct position if such accumulation is theoretically possible. Therefore, when the determined vertical angle is less than a threshold angle, the control unit may detect the presence of liquid only on the lens.

[0033] Additionally, a rain sensor, such as sensor 115, may be present, configured to determine the presence of rain at the luminaire, i.e., to determine that the luminaire is exposed to rain. The control unit can then be configured to consider the information from the rain sensor to determine the presence of liquid on the lens. While a rain sensor alone may not provide highly reliable results regarding the presence and amount of liquid on the lens, using a combination of the current from motor 108 and information from rain sensor 115 will improve the accuracy of determining the presence of liquid on lens 107 and reduce the number of false alarms.

[0034] The lighting fixture can be a moving head light, comprising a base, a yoke, and a head, wherein the yoke is rotatably arranged relative to the base and the head is rotatably arranged relative to the yoke, and a compartment with a light source and a lens is arranged in the head. Alternatively, only the head may be rotatably arranged relative to the yoke, or it may be directly connected to the base.

[0035] The lens can be arranged substantially perpendicular to the main light emission direction, and the electric motor can be configured to move the lens in a direction away from or toward at least one light source.

[0036] The luminaire may also include a deformable membrane 111 having a tubular shape extending from a first end to a second end and forming a recess (such as recess 120) opening to an external space outside the luminaire, wherein the first end of the membrane is attached to a lens and the second end of the membrane is attached to a sidewall of a compartment, and the sidewall may extend circumferentially around the lens. A control unit is then configured to determine the presence of liquid in the recess.

[0037] The lens can be the outermost component of the luminaire, through which light emitted by the light source in the main light emission direction passes. This means there are no other components or covers that could prevent liquid from being present in the recess 120. The size of the recess depends on the position of the lens 107 relative to the light source 110, and the closer the lens is to the light source 110, the larger the recess will be. The control unit can detect the presence of liquid on the lens based on the current consumed by the electric motor or the power used by the electric motor to move the lens.

[0038] An electric motor can be a stepper motor.

[0039] As discussed above, this application provides a simple and reliable liquid detection method that requires no additional components, as the current or power used by an electric motor can be used to determine the presence of liquid. This technology will also increase the expected lifespan of the luminaire because any gaskets or ceilings will not be subjected to potentially high water pressure if the liquid is not removed. Furthermore, the presence of liquid over a prolonged period can lead to water ingress and consequently product malfunction.

[0040] Measuring the current or power at the motor does not require a significant effort, especially compared to solutions that place rain sensors at the head section. Motor control also allows for the use of lower currents during normal operation, and may apply higher currents when higher currents are measured. Therefore, a load buffer is not required, and operational anomalies can be detected as discussed above to prevent further damage. Load sensing of the stepper motor is possible and can be achieved via closed-loop back electromotive force (EMF).

Claims

1. A lamp (100) comprising: - A compartment (140) configured to house at least one light source (110), said at least one light source being configured to emit light in the main light emission direction. - A lens (107) is movably arranged relative to the light source in the direction of the main light emission direction. - An electric motor (108) is configured to move the lens (107) relative to the light source in the direction of the main light emission direction. - A control unit (109, 112) configured to determine the current used by the electric motor to move the lens (107) in the main light emission direction, wherein the control unit (109, 112) is configured to detect the presence of liquid on the lens based on the determined current.

2. The luminaire (100) of claim 1, wherein the control unit is configured to detect the presence of liquid on the lens when the current is higher than a defined threshold current.

3. The luminaire (100) of claim 1 or 2, wherein the luminaire includes a movable head, the lens, the light source and the electric motor are located in the movable head, wherein the control unit is configured to initiate movement of the head when the presence of liquid is detected, so that the liquid is removed from the lens under the action of gravity.

4. The luminaire (100) as claimed in any of the preceding claims, wherein the lens (107) is an external lens, the lower surface of which faces the compartment and the upper surface of which faces the space outside the luminaire, wherein the control unit is configured to detect the presence of liquid on the upper surface.

5. The luminaire (100) as claimed in any of the preceding claims further includes an orientation sensor (116) configured to determine the vertical angle of the main light emission direction in space relative to the vertical direction of the Earth, wherein the control unit is configured to take into account the determined vertical angle to detect the presence of liquid on the lens.

6. The luminaire (100) of claim 5, wherein when the determined vertical angle is less than a threshold angle, the control unit (109, 112) detects the presence of liquid only on the lens.

7. The luminaire (100) as claimed in any of the preceding claims, further comprising a rain sensor (115) configured to determine that the luminaire is exposed to rainwater, wherein the control unit is configured to take into account the exposure to rainwater determined by the rain sensor to determine the presence of liquid on the lens.

8. The luminaire (100) as claimed in any of the preceding claims, wherein the luminaire is a moving head luminaire comprising a base (104), a yoke (103) and a head (102), wherein the yoke (103) is rotatably arranged relative to the base (104) and the head (102) is rotatably arranged relative to the yoke (103), wherein the compartment (140) having the light source and the lens is arranged in the head.

9. The luminaire (100) as claimed in any of the preceding claims, wherein the lens (107) is arranged substantially perpendicular to the main light emission direction, and the electric motor is configured to move the lens in a direction away from or toward the at least one light source.

10. The luminaire (100) of any of the preceding claims further includes a deformable membrane (111) having a tubular shape extending from a first end (118) to a second end (119) and forming a recess (120) opening to an external space outside the luminaire, wherein the first end of the membrane is attached to the lens, the second end of the membrane is attached to a sidewall of the compartment, and the sidewall extends circumferentially around the lens, wherein the control unit is configured to determine the presence of liquid in the recess.

11. The luminaire (100) as claimed in any of the preceding claims, wherein the lens (107) is the outermost part of the luminaire through which the light emitted by the light source toward the main light emission direction passes.

12. The luminaire (100) as claimed in any of the preceding claims, wherein the control unit (109, 112) is configured to detect the presence of liquid on the lens based on the power used by the electric motor to move the lens.

13. The luminaire (100) as claimed in any of the preceding claims, wherein the electric motor (108) is a stepper motor.

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