Abstract:
An image capturing device is disclosed. The image capturing device includes: a light-emitting component for generating a light ray; a light-guiding component for providing a first straight light-guiding path to guide the light ray generated by the light-emitting component toward a surface; and a sensor for sensing the light ray reflected by the surface to detect a movement of the image capturing device on the surface.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an image capturing device, and more specifically, to an image capturing device capable of providing straight light-guiding paths and comprising a light-guiding component that is composed of opaque material(s). 
   2. Description of the Prior Art 
   Image capturing technologies are popularly applied to several kinds of electronic devices, such as an optical mouse, or a fingerprint recognition device. An optical mouse according to a prior art is herein taken as an example. The operation of the optical mouse is described as follows. In general, a light-emitting component of the optical mouse emits a light ray that will arrive at a surface of an object (i.e., a surface of a desk or a mouse pad). Next, a sensor of the optical mouse senses the light ray reflected by the surface to generate a corresponding image. In this way, when the optical mouse moves on the surface, the optical mouse can capture a plurality of images using image recognition technologies, and then compute a displacement vector between the optical mouse and the surface. Finally, the optical mouse can generate a pointing signal corresponding to the displacement vector and send the pointing signal to a host (i.e., a computer). 
   Please refer to  FIG. 1 .  FIG. 1  is a cross-sectional diagram of an optical mouse  10  according to the prior art. The optical mouse  10  comprises a light-emitting component  12 , a support  14 , a transparent component  16 , a lens  18 , a mold  22 , a sensor  24 , a conducting support  26 , a diaphragm  28 , and a printed circuit board (PCB)  30 . A lighting system according to the prior art is composed of the light-emitting component  12 , the support  14  and the transparent component  16 . An image formation system according to the prior art is composed of the lens  18  (installed in the transparent component  16 ), the mold  22 , the sensor  24 , the conducting support  26  and the diaphragm  28 . For the lighting system, the light-emitting component  12  is a light emitting diode (LED) for emitting a light ray L 1 ′ toward a surface  31  of an object. The support  14  is utilized for fixing the light-emitting component  12 . The light ray L 1 ′ emitted by the light-emitting component  12  is guided toward an image formation area of the surface  31  with an appropriate angle by the transparent component  16  through reflection and refraction, wherein the light ray L 1 ′ is usually obliquely guided toward the image formation area of the surface  31 . 
   For the image formation system, the conducting support  26  is utilized for fixing the sensor  24  and for supplying power to the sensor  24 . The mold  22  is generated by an injection-molding process, where the material of the mold  22  is black plastic. The mold  22  is a container for protecting the sensor  24 , and comprises a lower cover. The lower cover has a hole so that it can be utilized as a diaphragm  28 . The diaphragm  28  is utilized for filtering out undesired light rays, in order to improve the quality of the optical image formation. In addition, the lens  18  is utilized for collecting and transmitting the reflective light rays on the surface  31  to the sensor  24 . The PCB  30  transmits the plurality of images sensed by the sensor  24  and outputs the images to a control component (not shown in FIG.  1 ). The control component then generates a pointing signal according to the images. The PCB  30  can supply power to the sensor  24  and the light-emitting component  12 , and can be connected to the conducting support  26  and the support  14  to assist in fixing the sensor  24  and the light-emitting component  12 . 
   The optical mouse  10  has the following disadvantages, however: 
   (1) Through the transparent component  16 , the angle of the light ray L 1 ′ emitted by the light-emitting component  12  is changed and arrives obliquely at the surface  31 , i.e. the light ray L 1 ′ is not detected evenly at the surface. 
   (2) The light ray L 1 ′ emitted by the light-emitting component  12  passes through air and then enters the transparent component  16 . Next, after two total reflections and passing through the transparent component  16  once more, the light ray L 1 ′ passes through air again and then arrives at the surface  31 . According to the prior art, utilizing the lens  18 , the light ray reflected by the surface  31  can be formed as an image on the sensor  24 . That is, the reflected light ray passes through air, enters the lens  18 , leaves the lens  18  and then goes into air again. Next, the reflected light ray enters a layer of a transparent silica gel on the sensor  24  (for protecting the sensor  24 ), and then arrives at the sensor  24 . Therefore, the intensity of the light ray decreases each time when the light passes through an interface formed by different mediums, causing the direction of the light ray to become disordered. 
   (3) The transparent component  16  is utilized for transmitting the light ray that arrives at the surface  31  and for transmitting another light ray reflected by the surface  31  to the sensor  24 . By this method, the effect of filtering out the noises is not good. 
   (4) The transparent component  16  is a light-pervious component. Several light rays L 1 ′ and L 2 ′ arriving at the surface  31  rather than the image formation area of the surface  31  will arrive at the sensor  24 , causing unnecessary interference resulting in a situation in which the images sensed by the sensor  24  are blurred. 
   (5) The lens  18  can collect the reflected light rays from the image formation area of the surface  31  and transmit them to the sensor  24 . The light illumination area is large, however, so many scattered light rays not from the image formation area may enter the sensor  24  through the transparent component  16 , resulting in a situation in which the images sensed by the sensor  24  are blurred. 
   SUMMARY OF THE INVENTION 
   One of the objectives of the claimed invention is therefore to provide an image capturing device capable of reducing the loss of light and further capable of decreasing noises, in order to solve the above-mentioned problem. 
   According to the claimed invention, an image capturing device is disclosed. The image capturing device comprises: a light-emitting component for generating a light ray; a light-guiding component for providing a first straight light-guiding path to guide the light ray generated by the light-emitting component toward a surface; and a sensor for sensing the light ray reflected by the surface to detect a movement of the image capturing device on the surface. 
   One of the major advantages and improvements is that a placement angle of a light-emitting component is adjusted so that a light ray can be directly guided towards a surface of an object, and then re-directed towards a sensor. In this way, repeated reflection and refraction can be avoided, and the light does not need to pass through many interfaces of different mediums, so the intensity of the light ray will not be weakened. A further advantage is that a light-guiding component is utilized for absorbing an undesired light ray (a noise). Hence, a better quality of an image formation of the sensor can be obtained, and thus the performance of the optical mouse can be improved. 
   These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a cross-sectional diagram of an optical mouse according to a prior art. 
       FIG. 2  is a functional block diagram of an optical mouse according to the present invention. 
       FIG. 3  is a cross-sectional diagram of the optical mouse shown in  FIG. 2 . 
       FIG. 4  is a cross-sectional diagram of another embodiment of the light-guiding component shown in  FIG. 3 . 
   

   DETAILED DESCRIPTION 
   Please refer to  FIG. 2 .  FIG. 2  is a functional block diagram of an optical mouse  50  according to the present invention. Please note that an optical pointing device (i.e. an optical mouse) is taken as an example to describe the technical characteristics of the present invention; however, the present invention is not limited to be applied to an optical pointing device. The present invention can be applied to any device with an image capturing mechanism, such as a fingerprint recognition device or other types of image recognition devices. As shown in  FIG. 2 , the optical mouse  50  is coupled to a host  60  (i.e., a computer). In the present embodiment, the optical mouse  50  comprises a light-emitting component  52 , a light-guiding component  53 , a sensor  55  (i.e., a CCD) and a control component  56 . A light-emitting diode (LED) chip  61  in the light-emitting component  52  is utilized for emitting a light ray L 1 . The light-guiding component  53  defines a straight light-guiding path for guiding the light ray L 1  toward a surface (i.e., a surface on which the optical mouse  50  lies). The light-guiding component  53  defines another straight light-guiding path for guiding a light ray L 2  towards the sensor  55 , wherein the light ray L 2  is the light ray L 1  reflected by the surface. Next, the sensor  55  can continuously detect the light rays L 2  to generate a plurality of images D corresponding to the surface. Afterwards, the control component  56  determines a direction and a displacement of the movement of the optical mouse  50  according to the images D, and generates a corresponding pointing signal Sp to inform the host  60 . It should be noted that in this embodiment of the present invention, the light ray L 1  is emitted by the LED chip  61  of the light-emitting component  52 , so the light rays L 1 , L 2  are in the visible spectrum. However, in other embodiments of the present invention, the light-emitting device of the light-emitting component  52  is not limited to be the LED chip  61 , and it can also be an infrared ray module or a laser diode. When these devices are utilized, the light rays L 1 , L 2  are outside the visible spectrum. For example, if the light ray L 1  is emitted by an infrared ray module of the light-emitting component  52 , the light rays L 1  and L 2  are infrared rays (IR), which are invisible light. The description of the light-emitting component  52  will be detailed in the following paragraph. 
   Please refer to  FIG. 2  and  FIG. 3 .  FIG. 3  is a cross-sectional diagram of the optical mouse  50  shown in  FIG. 2 . The optical mouse  50  on a surface  80  is utilized for detecting its own movement on the surface  80  and generating a pointing signal S p  according to the movement. As shown in  FIG. 3 , the optical mouse  50  comprises the following components installed in the housing  51  of the optical mouse  50 : the light-emitting component  52 , the light-guiding component  53 , a diaphragm  54 , the sensor  55 , a conducting support  57 , a protecting component  58  and a lens  63 . Please note that the operations and functions of the control component  56  are well known to those skilled in the art, and therefore the control component  56  is not shown in  FIG. 3 . This omission does not affect the present invention. 
   The conducting support  57  is utilized for fixing the light-emitting component  52  and the sensor  55 , and further for transmitting power to the light-emitting component  52  and the sensor  55 . In addition, as shown in  FIG. 3 , the conducting support  57  is connected to the diaphragm  54  for fixing the diaphragm  54 . The protecting component  58  is utilized for protecting the sensor  55  and the diaphragm  54 , and for fixing the corresponding positions of the sensor  55  and the diaphragm  54 . In this embodiment of the present invention, the light rays L 1 , L 2  are in the visible spectrum, so the protecting component  58  is made of a transparent resin, meaning the transparent resin is utilized for sealing up and fixing the sensor  55  and the diaphragm  54 . Moreover, the lens  63  is installed on one side of the protecting component  58  for adjusting the optical path of the light ray L 2  that is to be guided towards the sensor  55 . Please note that the lens  63  and the protecting component  58  can be individual components, meaning that the lens  63  is attached to the protecting component  58 . However, the protecting component  58  and the lens  63  can be formed as a whole. For example, during a process of forming the protecting component  58  using the transparent resin, the lens  63  can be formed on one side of the protecting component  58 . As shown in  FIG. 1 , the diaphragm  28  and the lens  18  of the optical mouse  10  according to the prior art cannot be integrated as a whole; however, the diaphragm  54  and the conducting support  57  of the optical mouse  50  according to the present invention can be integrated using a diaphragm component embedded technology. The protecting component  58  and the lens  63  formed as a whole are utilized for protecting and fixing the diaphragm  54  and the sensor  55 . Therefore, according to the present invention, the protecting component  58  can be utilized for connecting the lens  63  and the diaphragm  54 , so that before the light ray L 2  arrives at the sensor  55 , the number of times the light ray L 2  passes through an interface (where each interface is formed by a different medium) can be reduced. Please note that in other embodiments of the present invention, if the light rays L 1  and L 2  are outside the visible spectrum (i.e., an infrared ray), the protecting component  58  is composed of opaque material(s), and the sensor  55  and the diaphragm  54  are positioned in the opaque material(s). 
   The light-emitting component  52  comprises a light emitting diode (LED) chip  61  and a lens  62 , where the LED chip  61  is utilized for emitting a light ray L 1 . The lens  62  is installed on the LED chip  61  for adjusting an optical path of the light ray L 1 . For example, through utilizing the lens  62 , light rays emitted by the LED chip  61  having different directions can be adjusted to be parallel with each other. As shown in  FIG. 3 , the light-guiding component  53  comprises a plurality of channels  75  and  76 , respectively utilized for defining straight light-guiding paths. Therefore, the light ray L 1  is guided by the straight light-guiding path defined by the channel  75  toward the surface  80  through a hole of the base  78 . The light ray L 2  reflected from the surface  80  is guided by the straight light-guiding path defined by the channel  76  toward the sensor  55 . It should be noted that the placement angle of the light-emitting component  52  shown in  FIG. 3  is different from that of the light-emitting component  12  in  FIG. 1 . Therefore, the light ray L 1  emitted by the light-emitting component  52  can be directly guided toward the surface  80  through the straight light-guiding path. The other functions of the light-guiding component  53  will be detailed in the following paragraph. 
   The diaphragm  54 , installed in the protecting component  58 , is utilized for filtering the light ray guided toward the sensor  55 . Hence, the desired light ray L 2  can successfully pass through the diaphragm  54  and arrive at the sensor  55 . The sensor  55  senses the light ray L 2  to generate a plurality of images D corresponding to the surface  80 . As mentioned above, the control component  56  (shown in  FIG. 2 ) generates the pointing signal Sp according to the plurality of images. 
   As shown in  FIG. 3 , instead of passing through many interfaces formed by different mediums, the light ray L 1  can be directly guided toward the surface  80 . Hence, in contrast to the prior art, the intensity of the light ray L 1  can be preserved as much as possible and the light uniformity received by the surface  80  can be improved. In addition, the light ray L 2  only needs to pass through the lens  63 , and then directly arrive at the sensor  55 . Therefore, in contrast to the prior art, the number of times the light ray L 2  passes through an interface becomes less. In conclusion, for the optical mouse  50  according to the present invention, a decrease in light intensity of the light rays L 1  and L 2  incurred by transmission processes is less comparing with the prior art, meaning that is less. 
   As mentioned above, the light-guiding component  53  is mainly utilized for defining the straight light-guiding paths. The light-guiding component  53  can be further utilized for assisting in fixing the protecting component  58 , the light-emitting component  52  and the base  78  (a part of the housing  51 ). In the present embodiment, the light-emitting component  52  is installed in the channel  75 , meaning that a goal of fixing the position of the light-emitting component  52  can be achieved using the channel  75 . In addition, the channel  75  not only controls the angle of the light ray guided toward the surface  80  and the size of the light spot, but also absorbs light rays that are not parallel with the straight light-guiding paths. Therefore, the light rays L 1  that can arrive at the image formation area of the surface  80  is more parallel to the straight light-guiding path corresponding to the channel  75 . The functions of the channel  76  are listed as follows: 
   (1) Fixing the lens  63  in the channel  76  to achieve a goal of fixing the protecting component  58 . 
   (2) Fixing the correlative positions of the base  78  and the sensor  55 . 
   (3) Absorbing the light rays that are not parallel with the straight light-guiding path corresponding to the channel  76 , and also absorbing the light rays (the noises) not reflected from the image formation area of the surface  80 . For absorbing undesired light rays, the light-guiding component  53  according to the present invention is made of an opaque material, such as a black plastic material. In other words, the light-guiding component  53  can absorb many undesired light rays, only allowing the light rays that are more parallel with the straight light-guiding paths (the channels  75 ,  76 ) to pass through, such as the light rays L 1 , L 2 . In this way, the sensor  55  can obtain clear images to improve the performance of the optical mouse  50 . 
   As shown in  FIG. 3 , the light-guiding component  53  is installed on the base  78 ; however, the light-guiding component  53  and the base  78  also can be integrated into a single component. Please refer to  FIG. 4 .  FIG. 4  is a cross-sectional diagram of another embodiment of the light-guiding component  53  shown in  FIG. 3 . The base  78  and the light-guiding component  53  shown in  FIG. 3  are formed in an integrated manner; that is, the base of the housing  51  is designed to be the light-guiding component  53  and to comprise the channels  75  and  76 . In other words, in the present embodiment, a flat surface of the light-guiding component  53  corresponding to the surface  80  is utilized as the base of the optical mouse  50 . In this way, the cost of the optical mouse  50  according to the present invention can be significantly reduced and the structure design of the optical mouse  50  can become simpler. 
   In contrast to the prior art, there are two major advantages and improvements of the present invention. One of the advantages and improvements is that a placement angle of a light-emitting component is adjusted so that a light ray can be directly guided toward a surface of an object, and then re-directed toward a sensor. In this way, repeated reflection and refraction of the light can be avoided and the light ray does not need to pass through many interfaces formed by different mediums, so the intensity of the light ray will not be weakened. The other advantage is that a light-guiding component is utilized for absorbing an undesired light ray (a noise). Hence, a better quality of an image formation of the sensor can be obtained, meaning that the performance of the optical mouse can be improved. 
   Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.