Patent Publication Number: US-2003223130-A1

Title: Optical lenses having guiding surfaces

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to an optical lens that has contact surface so that the distance between two optical lenses can be precisely controlled.  
       BACKGROUND OF THE INVENTION  
       [0002] A conventional engagement between two lenses  101  and  102  is shown in FIG. 1 and the two respectively concave surface of the two lenses  101 ,  102  face with each other. The second lens  102  has contact surfaces  11  on which the first lens  101  is engaged. By controlling the sagitta, the distance between the two lenses  101 ,  102  can be controlled to a desired distance. However, when the second lens  102  is proceeded with centering process, if the sagitta increases Δd1, the diameter øD of the contact surfaces and this forces the side height d2 increases Δd2. The final distance d between the two lenses  101 ,  102  becomes Δd=Δd1+Δd2, and which is larger than Δd1. In other words, the change of the distance d between the two lenses  101 ,  102  will be larger than d1 which is controlled by machining processes.  
       SUMMARY OF THE INVENTION  
       [0003] In accordance with one aspect of the present invention, there is provided an assembly of optical lenses which comprises a first lens and a second lens. The first lens has a first concave surface which faces a second concave surface of the second lens. The second lens has a contact surface and a separation surface respectively defined in an outer periphery of the second concave surface. The separation surface is located closer to a center of the second concave surface than the contact surface second lens. The concave surface of the first lens is engaged with the contact surface.  
       [0004] The primary object of the present invention is to provide a contact surface defined in an outer periphery of a concave surface of one of two lenses and the other lens is engaged with the contact surface. The size of the contact surface is the same as the centering wheel so as to reduce the change resulted from machining between the two lenses.  
       [0005] The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, two preferred embodiments in accordance with the present invention. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0006]FIG. 1 is a cross sectional view to show two conventional lenses engaged with each other;  
     [0007]FIG. 2 is a cross sectional view to show two lenses of the present invention engaged with each other, and  
     [0008]FIG. 3 is a cross sectional view to show another embodiment of two lenses of the present invention engaged with each other. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0009] Referring to FIG. 2, the assembly of optical lenses of the present invention comprises a first lens  201  and a second lens  202 , both of which are glass lenses. The first lens  201  has a first concave surface  221  which faces a second concave surface  211  of the second lens  202 . The second lens  202  has a contact surface  222  and a separation surface  223  respectively defined in an outer periphery of the second concave surface  211 . The separation surface  223  is located closer to a center of the second concave surface  211  than the contact surface  222 . A protrusion corner is defined between the contact surface  222  and the separation surface  223 . The first concave surface  221  of the first lens  201  is engaged with the contact surface  222 . It is to be noted that the size of the contact surface  222  is the same as the centering wheel (not shown) so as to reduce the change resulted from machining between the two lenses  201 ,  202 .  
     [0010]FIG. 3 shows another embodiment of the present invention, wherein the first lens  301  has a first concave surface  311  which faces a second concave surface  321  of the second lens  302 . The second lens  302  has a contact edge  323  and a separation surface  322  is connected to the contact edge  323 . The separation surface  322  is located closer to a center of the second concave surface  321  than the contact edge  323 . The first concave surface  311  of the first lens  301  is engaged with the contact edge  323 . The advantage of the embodiment is that the centering wheel is not manufactured according to the diameter of the contact edge  323  so that the centering wheel is easily to make. The second concave surface  321  has a larger curvature than that of the first concave surface  311 . By this way, the amount of change of the contact surface of the centering wheel is reduced so as to simplify the processes of manufacturing.  
     [0011] The first lens is engaged with the contact surface or edge which is located at an outer periphery of the second concave surface so that the distance between the two lenses can be precisely controlled.  
     [0012] While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.