Patent Publication Number: US-2012044592-A1

Title: Filter conversion device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     Relevant subject matter is disclosed in the co-pending U.S. patent application (Attorney Docket No. US34600) having the same title, which is assigned to the same assignee as named herein. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a filter conversion device. 
     2. Description of Related Art 
     Camera filters are transparent or translucent optical elements that alter the properties of light entering the camera lens for improving the image being captured. Filters can affect contrast, sharpness, highlight flare, color, and light intensity, either individually, or in various combinations. For cameras, which work in the light and in the dark, a conversion device is needed. The conversion device selects a filter in the light and a different filter for dark. However, the camera cannot ensure whether the control signal, which the camera has received to select the corresponding filter is correct. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a schematic diagram of an exemplary embodiment of a filter conversion device. 
         FIG. 2  is a circuit diagram of the filter conversion device of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure, including the accompanying drawings, is illustrated by way of example and not by way of limitation. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
     Referring to  FIGS. 1 and 2 , an exemplary embodiment of a filter conversion device includes a first filter  10 , a second filter  12 , a motor M, a body  16 , a comparator U, and two resistors R 1  and R 2 . The filter conversion device is set between a lens and an image sensor of a camera  1 , to select the first filter  10  or the second filter  12  in the light or dark. 
     The motor M and the comparator U are connected to a processor  20  and a control circuit  22  of the camera with a connector  19 . The motor M rotates backward or forward according to a control signal from the processor  20  and the control circuit  22 , to adjust the positions of the first filter  10  and the second filter  12 . The comparator U detects the control signal transmitted to the motor M and feeds back the detection result to the processor  20 , to determine whether the control signal is correct. 
     The connector  19  includes first to fourth terminals P 1 -P 4 . The first terminal P 1  is connected to the processor  20  with the control circuit  22  of the camera. The second terminal P 2  and the third terminal P 3  are respectively connected to two terminals of the motor M. The second terminal P 2  is also connected to an inverting terminal of the comparator U with the resistor R 1 , and the third terminal P 3  is also connected to a non-inverting terminal of the comparator U with the resistor R 2 . The fourth terminal P 4  of the comparator U is connected to an output terminal of the comparator U. A power terminal of the comparator U is connected to a power source Vcc, and a ground terminal of the comparator U is grounded. 
     If the voltage of the second terminal P 2  of the connector  19  is greater than the voltage of the third terminal P 3  of the connector  19 , the motor M rotates forward. As a result, the first filter  10  and the second filter  12  move left ( FIG. 1 ), and the first filter  10  is selected. When the voltage of the second terminal P 2  of the connector  19  is less than the voltage of the third terminal P 3  of the connector  19 , the motor M rotates backward. As a result, the first filter  10  and the second filter  12  move right, and the second filter  12  is selected. 
     If the processor  20  outputs a first control signal to control the motor M to rotate forward to move the first filter  10  and the second filter  12  left, the control circuit  22  outputs a first voltage signal Va and a second voltage signal Vb to the two terminals of the motor M according to the first control signal. The comparator U compares the first voltage signal Va with the second voltage signal Vb. If the first voltage signal Va is greater than the second voltage signal Vb, the comparator U feeds back a high level signal to the processor  20 . The processor  20  determines that the control signal, which the motor M receives to select the corresponding filter is correct. If the first voltage signal Va is less than the second voltage signal Vb, the comparator U feeds back a low level signal to the processor  20 . The processor  20  determines that the control signal, which the motor M receives to select the corresponding filter is incorrect. At this time, the camera warns the operators to check the camera. 
     If the processor  20  outputs a second control signal to control the motor M to rotate backward to move the first filter  10  and the second filter  12  right. The control circuit  22  outputs a third voltage signal Va′ and a fourth voltage signal Vb′ to the two terminals of the motor M according to the second control signal. The comparator U compares the third voltage signal Va′ with the fourth voltage signal Vb′. If the third voltage signal Va′ is less than the fourth voltage signal Vb′, the comparator U feeds back a low level signal to the processor  20 . The processor  20  determines that the control signal, which the motor M receives to select the corresponding filter is correct. If the third voltage signal Va′ is greater than the fourth voltage signal Vb′, the comparator U feeds back a high level signal to the processor  20 . The processor  20  determines that the control signal, which the motor M receives to select the corresponding filter is incorrect. At this time, the camera warns operators to check the camera. 
     The foregoing description of the embodiments of the disclosure has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above everything. The embodiments were chosen and described in order to explain the principles of the disclosure and their practical application so as to enable others of ordinary skill in the art to utilize the disclosure and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those of ordinary skills in the art to which the present disclosure pertains without departing from its spirit and scope. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.