Patent Publication Number: US-2004041088-A1

Title: Digital CMOS sensor

Description:
BACKGROUND OF THE INVENTION  
       [0001] A present invention is related to a digital CMOS sensor in which a color filtering layer is directly vapor deposited on a chip to shorten light path and reduce the volume. In addition, the filtering layer serves to prevent the chip, metallic lead and lead frame from being oxidized.  
       [0002] A digital image technique has been widely applied to image shooting instruments such as digital camera, image scanner, etc. FIG. 6 shows the digital image lens combination of the digital camera. A CMOS sensor  61  is disposed on a circuit board  6 . The CMOS sensor  61  has a chip  62 . A lens seat  7  is disposed above the CMOS sensor  61 . The lens seat  7  has a focusing lens  71  for focusing the image onto the chip  62  of the CMOS sensor  61 .  
       [0003] Through the lens, the image signal is sent by the chip  62  to a digital signal processor (DSP) for converting the analog signal into digital signal. The digital signal is provided for a microprocessor for color recovery operation such as zooming, automatic exposure and white balance. The chip  62  of the CMOS sensor  61  is relatively sensitive to infrared ray and red light. In order to achieve more lively color of the image and avoid bias of the color of the image, a filtering lens  72  is disposed between the focusing lens  71  and the CMOS sensor  61 . The filtering lens  72  is formed of a glass piece on which a color filtering layer  73  is deposited. The filtering layer  73  serves to filter and compare Ming blue, Oriental red, yellow, green (auxiliary color filter) and red, green, blue (original color filter) light to regulate the shot picture and achieve better image and color.  
       [0004] However, the filtering lens  72  will elongate the light path so that the volume of the digital image lens combination cannot be reduced. As shown in FIG. 7, the filtering lens  72  will refract the light beam so that the light beam cannot be projected to the image sensing area  621  of the chip  62  of the CMOS sensor  61 . Therefore, it is necessary to increase the distance between the position of the focusing lens  71  and the chip  62  so as to project the light beam onto the image sensing area  621 . Accordingly, the length of the digital image lens combination will be elongated. This makes impossible to apply such digital image lens combination to various minitype digital image instruments.  
       [0005] Furthermore, as shown in FIG. 8, the chip  62  of the CMOS sensor  61  is made of metallic material and the lead frame  622  connecting with the lead of the chip  62  is also metal-made. Therefore, a problem of oxidization exists. Although the CMOS sensor has been packaged, the humidity in the air will still result in oxidization of the chip, lead and lead frame. This will affect the image quality.  
       SUMMARY OF THE INVENTION  
       [0006] It is therefore a primary object of the present invention to provide a digital CMOS sensor in which a color filtering layer is directly vapor deposited on the chip. When applied to the digital image lens combination of a digital image instrument, it is unnecessary to further dispose a filtering lens. Therefore, the total volume of the digital image lens combination can be reduced, whereby the digital CMOS sensor can be applied to a small-size digital image instrument.  
       [0007] It is a further object of the present invention to provide the above digital CMOS sensor in which the filtering layer vapor deposited on the chip of the CMOS sensor is also able to prevent the chip, metallic lead and lead frame from being oxidized.  
       [0008] According to the above objects, the digital CMOS sensor of the present invention has a chip on which a color filtering layer is vapor deposited for filtering specific frequency of optical wave and comparing the optical wave.  
       [0009] The present invention can be best understood through the following description and accompanying drawings wherein: 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0010]FIG. 1 is a sectional view showing that the present invention is applied to a digital image lens of a digital camera;  
     [0011]FIG. 2 shows that a filtering layer is vapor deposited on the chip of the present invention;  
     [0012]FIG. 3 is a sectional view showing that the present invention is directly disposed on a circuit board;  
     [0013]FIG. 4 shows a second embodiment of the present invention, in which a filtering layer is first vapor deposited on the crystal lattice;  
     [0014]FIG. 5 shows that after cut, the CMOS sensor of the second embodiment of the present invention has a filtering layer;  
     [0015]FIG. 6 is a sectional view showing that a conventional CMOS sensor is applied to a digital image lens of a digital camera;  
     [0016]FIG. 7 shows that the light path of the conventional CMOS sensor is elongated; and  
     [0017]FIG. 8 is a front view of the conventional CMOS sensor. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0018] Please refer to FIGS. 1 and 2. The present invention is related to a digital CMOS sensor. For easy illustration, a digital image lens combination applicable to digital camera is exemplified. The digital image lens combination has a CMOS sensor  2  disposed on a circuit board  1 . The CMOS sensor  2  includes a chip  21  having an image sensing area  22 . The periphery of the chip  21  has a lead frame  23  connecting with the lead of the chip  21  for connecting with the circuit of the circuit board  1 . A lens seat  4  is disposed above the CMOS sensor  2 . The lens seat  4  has a focusing lens  41  for focusing the image onto the image sensing area  22  of the chip  21 .  
     [0019] By way of vapor deposition, a filtering layer  3  is deposited on the surface of the CMOS sensor  2  and the lead frame  23 . The filtering layer  3  has a color filtering material for filtering specific frequency of optical wave and comparing the optical wave.  
     [0020] The color filtering layer  3  is vapor deposited on the CMOS sensor  2  so that it is unnecessary to further dispose a color filtering lens for filtering specific frequency of optical wave and comparing the optical wave. Therefore, the total volume of the digital image lens combination can be reduced. This makes it possible to apply the digital image lens combination to a small-size digital image device.  
     [0021] Moreover, the filtering layer  3  is vapor deposited on the surface of the chip  21  of the CMOS sensor  2  and the lead frame  23  to achieve filtering effect. In addition, the filtering layer  3  serves to prevent the metallic chip  21 , metallic lead and lead frame  23  in the CMOS sensor  2  from being oxidized due to humidity in the air.  
     [0022] Especially, referring to FIG. 3, in the case that the CMOS sensor  2  is directly disposed on the circuit board  1  without packaging, there is more possibility of contact of the chip  21  and lead frame  23  with the air. Therefore, the chip  21  and lead frame  23  will be more deeply affected by the humidity. However, the filtering layer  3  vapor deposited on the chip  21  of the CMOS sensor  2  and the lead frame  23  is able to prevent the metallic chip  21 , metallic lead and lead frame  23  in the CMOS sensor  2  from being oxidized.  
     [0023]FIGS. 4 and 5 show a second embodiment of the present invention, in which the chip  21  of the CMOS sensor  2  is a crystal lattice  24  without cutting and the filtering layer  3  is vapor deposited on the crystal lattice  24 . By means of masking technique, the filtering layer  3  can be vapor deposited on the image sensing area  22  of each chip  21 . After cut, the chip  21  has the filtering layer  3 . This saves the manufacturers from troublesome respective vapor deposition procedures after packaged so that the manufacturing cost is lowered.  
     [0024] The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention.