Patent Publication Number: US-2023156311-A1

Title: Optical engine accommodating multiple light sources

Description:
RELATED APPLICATIONS 
     The present application is a continuation application of U.S. application Ser. No. 17/375,035, filed on Jul. 14, 2021, which is a continuation application of U.S. application Ser. No. 16/547,568, filed on Aug. 22, 2019, which claims the priority benefit of U.S. Provisional Application Ser. No. 62/756,110, filed Nov. 6, 2018, the full disclosures of which are hereby incorporated by reference herein in their entirety. 
     To the extent any amendments, characterizations, or other assertions previously made (in this or in any related patent applications or patents, including any parent, sibling, or child) with respect to any art, prior or otherwise, could be construed as a disclaimer of any subject matter supported by the present disclosure of this application, Applicant hereby rescinds and retracts such disclaimer. Applicant also respectfully submits that any prior art previously considered in any related patent applications or patents, including any parent, sibling, or child, may need to be re-visited. 
    
    
     BACKGROUND 
     1. Field of the Disclosure 
     This disclosure generally relates to an optical engine having multiple light sources and, more particularly, to an optical engine having multiple light sources adapted to navigation devices. 
     2. Description of the Related Art 
     The optical navigation device uses a light source to illuminate a working surface and uses an image sensor to capture reflected light from the working surface to generate image frames. A processor calculates a moving distance and/or speed of the navigation device with respect to the working surface according to the image frames. 
     However, different working surfaces generally have different reflectivity that causes image features contained in the image frames to have apparent variations. Accordingly, a navigation device capable of distinguishing working surfaces of different materials is required. 
     SUMMARY 
     The present disclosure provides a barrier structure of an optical engine accommodating multiple light sources to be switched corresponding to different working surfaces to be applicable to the operation on different working surfaces. 
     The present disclosure further provides a barrier structure of an optical engine accommodating multiple light sources and preventing the interference between emission light and reflected light of different light sources. 
     The present disclosure provides an optical engine including a first light source, a lens, a second light source, an image sensor, a first plane surface and a second plane surface. The first plane surface has a first opening connecting to a first space below the first plane surface, wherein the first light source is accommodated in the first space, and the first opening exposes a part of the first light source. The second plane surface includes a second opening and a third opening. The second opening is connected to a second space below the second plane surface, wherein the lens is accommodated in the second space, and the second opening exposes the lens. The third opening is connected to a third space below the second plane surface, wherein the second light source and the image sensor are accommodated in the third space, and the third opening exposes the second light source and a part of a sensing surface of the image sensor. 
     The present disclosure further provides an optical engine including a first light source, a lens, a second light source, an image sensor, a first plane surface, a second plane surface and a wall. The first plane surface has a first opening connecting to a first space below the first plane surface, wherein the first light source is accommodated in the first space, and the first opening exposes the first light source. The second plane surface includes a second opening and a third opening. The second opening is connected to a second space below the second plane surface, wherein the lens is accommodated in the second space, and the second opening exposes the lens. The third opening is connected to a third space below the second plane surface, wherein the second light source and the image sensor are accommodated in the third space, and the third opening exposes the second light source and a part of a sensing surface of the image sensor. The wall perpendicularly extends between the first space and the second space, and has a first protrusion structure transversely extending inside the first space to tilt the first light source to direct to a direction away from the second opening. 
     The present disclosure further provides an optical engine including a first light source, a lens, a second light source, an image sensor, a first plane surface, a second plane surface and a third plane surface. The first plane surface has a first opening connecting to a first space below the first plane surface, wherein the first light source is accommodated in the first space, and the first opening exposes a part of the first light source. The second plane surface is lower than the first plane surface, and has a second opening connecting to a second space below the second plane surface, wherein the lens is accommodated in the second space, and the second opening exposes the lens. The third plane surface is higher than the second plane surface, and has a third opening connecting to a third space below the third plane surface, wherein the second light source and the image sensor are accommodated in the third space, and the third opening exposes the second light source and a part of a sensing surface of the image sensor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects, advantages, and novel features of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
         FIG.  1    is a solid diagram of an optical engine according to one embodiment of the present disclosure. 
         FIG.  2    is an upper view of an optical engine according to one embodiment of the present disclosure. 
         FIG.  3    is a cross-sectional view of the optical engine and a hood alone line A-A′ in  FIG.  2   . 
         FIG.  4    is a cross-sectional view of an optical engine according to another embodiment of the present disclosure. 
         FIG.  5    is a cross-sectional view of an optical engine according to an alternative embodiment of the present disclosure. 
         FIG.  6    is another solid diagram of an optical engine according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT 
     It should be noted that, wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     The present disclosure provides an optical engine having multiple light sources. The optical engine has a barrier structure for protecting the elements therein and preventing the interference between emission light of different light sources and reflected light from a working surface to improve the identification accuracy. The optical engine is adapted to, for example, a navigation device operating on the working surface, e.g., a cleaning robot, but not limited thereto. 
     Referring to  FIGS.  1  to  3   ,  FIG.  1    is a solid diagram of an optical engine  100  according to one embodiment of the present disclosure;  FIG.  2    is an upper view of an optical engine  100  according to one embodiment of the present disclosure; and  FIG.  3    is a cross-sectional view of the optical engine  100  alone line A-A′ in  FIG.  2    and a hood  20 . 
     The optical engine  100  includes a first light source  12 , a lens  14 , a second light source  16 , an image sensor  18 , a substrate  11  and a barrier structure  13  disposed on the substrate  11 , wherein the barrier structure  13  is attached to the substrate  11  via glue or screwing member without particular limitations. The substrate  11  is a printed circuit board (PCB) or a flexible substrate without particular limitations. In some embodiments, the optical engine  100  further includes a hood  20  (further referring to  FIG.  6   ) arranged on the substrate  11  and covering the barrier structure  13  for dust protection and blocking ambient light. The hood  20  is attached to the substrate  11  via glue or screwing member without particular limitations. 
     The barrier structure  13  is preferably not transparent to the light emitted by the first light source  12  and the second light source  16 . The material of the barrier structure  13  is not particularly limited, such as plastic, and is manufactured by, for example, injection molding. The barrier structure  13  has a first plane surface  132  and a second plane surface  134  parallel to the substrate  11 . In one aspect, the first plane surface  132  is higher than the second plane surface  134 . The first plane surface  132  has a first opening  131  to have a first space therebelow. The second plane surface  134  has a second opening  133  and a third opening  135  adjacent to each other to respectively have a second space and a third space therebelow. Said openings and spaces are used as the tunnel for light beams propagating in and out the barrier structure  13 . 
     The first light source  12  is arranged inside the first opening  131  (i.e. in the first space) and electrically coupled to the substrate  11  to receive control signals and power therefrom. The first light source  12  is described herein using a light emitting diode as an example (e.g., infrared light emitting diode, but not limited to). The first light source  12  is used to generate emission light leaving the first opening  131  in a direction substantially perpendicular to the substrate  11  to illuminate the working surface S. For fixing the first light source  12 , in some aspects the barrier structure  13  further includes a protrusion structure  136  pressing against the first light source  12 . It should be mentioned that although  FIG.  3    shows that the protrusion structure  136  perpendicularly extends from the barrier structure  13  in a transverse direction, it is only intended to illustrate but not to limit the present disclosure. In other aspects, the protrusion structure  136  extends from the barrier structure  13  with a tilt angle (e.g., upward or downward) to press against a surface of the first light source  12 . In other aspects, the side wall surrounding the first opening  131  (or the first space) of the barrier structure  13  is manufactured to have a larger thickness to directly attach to the side of the first light source  12  to fix the first light source  12  therein without forming the transverse protrusion structure  136 , i.e. the first light source  12  just fitting the first space. 
     The lens  14  is arranged inside the second opening  133  (or the second space) to guide reflected light from the working surface S and associated with the first light source  12  to the image sensor  18 . In some aspects, in order to be able to arrange the lens  14  into the second opening  133 , the lens  14  is cut to reshape the appearance thereof (e.g., having non-circular cross-section). It should be mentioned that although  FIG.  3    shows that a single lens  14  is arranged inside the second opening  133 , the present disclosure is not limited thereto. Corresponding to different applications, a lens set having more than one lens is arranged in the second opening  133 , and the barrier structure  13  is formed with a structure to carry said lens set. 
     The second light source  16  is arranged inside the third opening  135  (i.e. in the third space) and electrically coupled to the substrate  11  to receive control signals and power therefrom. The second light source  16  is described herein using a laser diode as an example (e.g., infrared laser diode, but not limited to). The second light source  16  is used to generate emission light leaving the barrier structure  13  via the third opening  135  to illuminate the working surface S. In one aspect, the second light source  16  and the first light source  12  respectively illuminate different areas on the working surface S. In one aspect, there is no any optical component arranged inside the third opening  135  to expand or shrink emission light generated by the second light source  16 . 
     The image sensor  18  is arranged under the third opening  135  (i.e. in the third space) and electrically coupled to the substrate  11  to receive/send signals therethrough. The image sensor  18  is a CMOS image sensor, a CCD image sensor or the like. In one aspect, the second light source  16  and the image sensor  18  are encapsulated in a same chip package, which is disposed on the substrate  11  and electrically connected thereto. In this case, a blocking layer is preferably formed between the second light source  16  and the image sensor  18  to prevent the emission light from the second light source  16  from directly being received by the image sensor  18 . In other aspects, said chip package further has a processor, e.g., an application specific integrated circuit (ASIC) or a digital signal processor (DSP), to process image signals acquired by the image sensor  18 . 
     The image sensor  18  has a sensing surface (e.g., the bottom surface in the figure). A part of the sensing surface overlaps the third opening  135  and another part of the sensing surface overlaps the second opening  133  and the lens  14 . In this way, a part of the sensing surface of the image sensor  18  receives reflected light that enters the barrier structure  13  via the third opening  135 , wherein the reflected light is formed after being emitted by the second light source  16  and then reflected by the working surface S. Another part of the sensing surface of the image sensor  18  receives reflected light via the lens  14  in the second opening  133 , wherein the reflected light is formed after being emitted by the first light source  12  and then reflected by the working surface S. 
     In this embodiment, to prevent the reflected light associated with the first light source  12  from being received by the image sensor  18  via the third opening  135 , the first plane surface  132  blocks a part of the first light source  12  (e.g.,  FIGS.  2  and  3    showing a half being blocked and the other half being exposed) to block reflected light of the emission light generated by the first light source  12  from entering the third opening  135 . The area being blocked is determined according to a transverse distance between the first light source  12  and the image sensor  18  as well as a vertical distance between the first light source  12  and the working surface S. The inner surface of the first plane surface  132  is directly attached to the top of the first light source  12  or separated from the first light source  12 . 
     In this embodiment, different areas of the image frame captured by the image sensor  18  is used by a processor (included in the chip package or coupled to the image sensor  18  via the substrate  11 ) to calculate the detection result of different light sources. Other arrangements are used in the present disclosure to avoid the interference between light from different light sources. 
     Referring to  FIG.  4   , it is a cross-sectional view of an optical engine and a hood  20  according to another embodiment of the present disclosure. In this embodiment, the first plane surface  132  does not cover upon the first light source  12 . By arranging the first light source  12  to generate emission light leaving the first opening  131  in a direction tilted away from the lens  14  (e.g.,  FIG.  4    showing toward a lower-right direction), reflected light of the emission light generated by the first light source  12  only reaches the second opening  133  without entering the third opening  135 . 
     The difference between this embodiment and that of  FIG.  3    is that the first light source  12  is arranged with a tilted angle (i.e. an emission axis thereof not perpendicular to the substrate  11 ) to realize the objective of eliminating the interference. The arrangement of other components is identical to  FIG.  3   , and thus details thereof are not repeated herein. 
     In this embodiment, as the first light source  12  is arranged with a tilt angle, at least one protrusion structure (e.g., two protrusion structures  136  and  136 ′ being shown herein, but not limited to) is selected to form inside the first opening  131  to press again and fix the first light source  12 . In other aspects, the size of the first opening  131  (or first space) is manufactured to fit a size of the first light source  12  such that when the first light source  12  is inserted into the first space, the first light source  12  is fixed and has the predetermined tilt angle. 
     Referring to  FIG.  5   , it is a cross-sectional view of an optical engine and a hood  20  according to an alternative embodiment of the present disclosure. In this embodiment, the barrier structure  13  has a first plane surface  132 , a second plane surface  134  and a third plane surface  134 ′, wherein the first plane surface  132  has a first opening  131  to have a first space therebelow; the second plane surface  134  has a second opening  133  to have a second space therebelow; and the third plane surface  134 ′ has a third opening  135  to have a third space therebelow, and the second plane surface  134  is lower than the first plane surface  132  and the third plane surface  134 ′. More specifically, in this embodiment, a height of the side wall of the third opening  135  is increased to prevent reflected light, formed after being emitted by the first light source  12  and reflected by the working surface S, from entering the third opening  135 . In one aspect, the first plane surface  132  and the third plane surface  134 ′ have an identical height, but not limited to. The difference between this embodiment and that of  FIG.  3    is that the side wall surrounding the third opening  135  (or third space) is increased to be higher than the second plane surface  134 . The arrangement of other components is identical to  FIG.  3    and thus details thereof are not repeated herein. 
     The hood  20  preferably has a tilted part  201  and a transverse part  203  therein (as shown in  FIG.  3 - 5   ) that are transparent to the emission light of the second light source  16  and the first light source  12 , respectively, or transparent to the sensing spectrum of the image sensor  18 . The tilted part  201  preferably causes the emission light from the second light source  16  to be refracted (e.g., toward lower-right direction in figure) after passing through, and a refracted angle is arranged to cause the reflected light from the working surface S associated with the second light source  16  to propagate to the image sensor  18  via the third opening  135  instead of via the second opening  133 . Preferably, the emission light of the first light source  12  is not refracted while passing through the transverse part  203 . 
     In an alternative aspect, the transverse part  203  is arranged in the way to refract the emission light from the first light source  12  to bend toward right side of the figure to have the same effect of  FIG.  4   . In this way, the first light source  12  is not arranged in a tilt angle to prevent the emission light of the first light source  12  to be reflected to enter the third opening  135 . 
     Although the above embodiments described that the reflected light associated of the first light source  12  does not enter the third opening  135  and the reflected light associated with the second light source  16  does not enter the second opening  133 , it is appreciated that this only means most energy of the emission light of the first light source  12  and the second light source  16  does not enter the corresponding opening. As the working surface S has the light scattering effect, a small part of the emission light of the first light source  12  is still scattered to the third opening  135  and a small part of the emission light of the second light source  16  is still scattered to the second opening  133 . As the energy of the scattered light is relatively small, detecting efficiency is considered not being affected thereby. 
     It is appreciated that the shape of every opening in the above embodiments is only intended to illustrate but not to limit the present disclosure. 
     As mentioned above, to normally operate on different working surfaces, in addition to enhance the post-processing ability of the processor, utilizing multiple light sources to operate corresponding to different working surfaces is another choice. Accordingly, the present disclosure provides an optical engine for navigation devices (e.g.,  FIGS.  1 - 6   ) that light up different light sources when a type of the working surface changes to improve the image feature in the image frames. By arranging a barrier structure, the optical engine of the present disclosure can eliminate the interference between emitted light and reflected light from different light sources to improve the identification accuracy. 
     Although the disclosure has been explained in relation to its preferred embodiment, it is not used to limit the disclosure. It is to be understood that many other possible modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the disclosure as hereinafter claimed.