Patent Publication Number: US-2005140980-A1

Title: Optical measurement apparatus

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to an optical measurement apparatus, especially to be used to detect the optical characteristics of array-type samples by this optical measurement apparatus.  
      2. Description of the Prior Art  
      An optical measurement apparatus is popularly used in the bio-medical research fields, such as for decoding the sequence of genes, analyzing a protein structure, and developing genetic medication. For example, in the biochemical tests for a biochip, each grid of the microarray structure is capable of putting tens of thousands of chains of deoxyribonucleic acid (DNA) in it. And the optical measurement apparatus will be used to recognize the fluorescent marks generated from the matching reactions between the tested sample and the DNA. Different colors of the fluorescent marks will be compared and transformed as meaningful data by means of a computer.  
      As shown in  FIG. 1 , a conventional optical measurement apparatus  10  comprises a control system  12 , a laser system  14 , an excitation mirror  16 , an optical system  18 , a base  26 , a two-dimensional positioning system  28 , an emission mirror  30 , a light filter  32 , a focusing lens  34 , an aperture stop  36 , and a sensor  38 . When the system is operating, the laser system  14  emits continuously excitation light  20 . After the excitation light  20  passes through the optical system  18  to be projected onto a microarray  24  on the base  26 , the two-dimensional positioning system  28  will be moved to read the photic signal of each grid on the microarray  24 . Each photic signal on the microarray  24  will be transmitted by the emission light  22  produced after the excitation light  20  illuminates the fluorophore on each grid of the microarray  24 . After passing through the optical system  18 , the emission mirror  30 , and the light filter  32 , the emission light  22  will be focused by the focusing lens  34  to pass the aperture stop  36 . Further, the emission light  22  will be projected onto the sensor  38  and the sensor  38  will read the photic signal of each grid on the microarray  24 . Generally, the sensor is often a photomultiplier.  
      The aforementioned optical measurement apparatus  10  has a problem. The cost of the optical measurement apparatus  10  is so high that it prevents the optical measurement apparatus  10  from being prevalent in each research center or each hospital because the light source of the excitation light  20  is an expensive laser system  14 . Further, the optical mechanism applied to a laser system  14  is too complicated to maintain and the frequency used by the optical measurement apparatus  10  is limited. Accordingly, there is a need for a light source of low cost.  
      In the other hand, because the way of scanning in the conventional optical measurement apparatus  10  is the way of continuous single-point-scanning, the time spent on scanning is too long and the continuous laser excitation light  20  causes a problem so that it is difficult for the sensor  38  to distinguish the desired signals from noise when the sensor  38  reads a signal. As a result, there is a need to have an efficient light guiding and signal receiving mechanism to swiftly and correctly read the fluorescent signals from the microarray  24 .  
      Because the way in scanning of the conventional optical measurement apparatus  10  is a way of continuous single-point-scanning, the microarray  24  has to be implemented on the base  26 , which moves two-dimensionally. In addition to the complicated optical mechanism, the space taken by the conventional optical measurement apparatus  10  is very big. The power consumption of the laser system  14  is also so high that the laser system wastes electric power. As a result, there is a need for an optical measurement apparatus that takes smaller space and consumes a lower amount of electric power.  
     SUMMARY OF THE INVENTION  
      One purpose of the present invention is to provide an optical measurement apparatus for detecting the array-type samples. A light source and guiding module composed of a light source module and a light-guiding apparatus optical measurement apparatus used for forming a linear light, which is excited from an area light source module and passes through a wedged-shaped light-guiding apparatus. The area light source module comprises a light array formed by a plurality of light-emitting diodes (LEDs) or a plurality of organic light-emitting diodes (OLEDs), taking the place of the conventional laser system for the expensive cost and inconvenient maintaining. The optical measurement apparatus further comprises a platform for supporting and transporting the test sample and moving only in one-dimensional direction, simplifying the complexity of the optical mechanism of two-dimensional movement and single-point-scanning mode of the conventional optical measurement apparatus.  
      Another purpose of the present invention is provided with a linear or area charge coupled device (CCD) in a receiving module, taking the place of the photomultiplier in the prior art to reduce inaccuracy and processing time in receiving the image signal.  
      The present invention uses a light source and guiding module and a CCD to replace the laser system and the photomultiplier of the prior art. Compared with the conventional optical measurement apparatus, the optical measurement apparatus of the present invention has some advantages such as smaller space taken, lower cost, reduction of power consumption, and flexibility of design, intermittent excitation light, and variable frequencies of excitation light. Accordingly, the design and production cost of the whole optical measurement apparatus is lowered substantially and further the correct and swift scanning for an array-type sample is realized. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The foregoing aspects and many of the attendant advantages of this present invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:  
       FIG. 1  shows an illustrative chart of a conventional optical measurement apparatus;  
       FIG. 2A  shows a perspective drawing of a straight-line-type wedge-shaped light-guiding apparatus according to the present invention;  
       FIG. 2B  is a top view of a straight-line-type wedge-shaped light-guiding apparatus according to the present invention;  
       FIG. 2C  shows a perspective drawing of an arc-line-type wedge-shaped light-guiding apparatus according to the present invention;  
       FIG. 2D  is a top view of an arc-line-type wedge-shaped light-guiding apparatus according to the present invention;  
       FIG. 3  shows an optical measurement apparatus according to the present invention; and  
       FIG. 4  shows another optical measurement apparatus according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Some embodiments of the invention will be described exquisitely as below. Besides, the invention can also be practiced extensively in other embodiments. That is to say, the scope of the invention should not be restricted by the proposed embodiments. The scope of the invention should be based on the claims proposed later.  
       FIG. 2A  and  FIG. 2B  are the perspective drawings and the top view of a straight-line-type wedge-shaped light-guiding apparatus of the present invention. The straight-line-type wedge-shaped light-guiding apparatus is configured between the light source module and the test sample, guiding an area light emitted from the light source module to be a linear light irradiating to the test sample. The geometric type of the light-guiding apparatus is not limited of above descriptions.  FIG. 2C  and  FIG. 2D  show the perspective drawing and the top view of an arc-line-type wedge-shaped light-guiding apparatus according to the present invention. The arc-line-type wedge-shaped light-guiding apparatus is capable of guiding area light to linear light in a direction different from the exciting direction of light. The exterior of the light-guiding apparatus of the present invention could be selected from a combination of a plurality of reflection elements such as stainless steel sheets. And the filler inside the light-guiding apparatus could be selected from the group consisting of glass, acrylics, polycarbonate (PC) and other materials to assist the light transmitted with a way of total reflection or partial reflection within the light-guiding apparatus. In addition, the light-guiding apparatus could be composed of a plurality of light guiding pipes such as bundle fibers. In the present invention, the light source module and the light-guiding apparatus could be integrated into a light source and guiding module for providing and transmitting a light to the test sample.  
      One preferred embodiment according to the present invention is shown in  FIG. 3 . An optical measurement apparatus  40 , with the reflective formation of image, is provided with a light array  42 , an arc-line-type wedge-shaped light-guiding apparatus  44 , a platform  47 , an emission mirror  50 , a focusing lens  52 , and a linear charge coupled device  54 . The light array  42  and its control unit (not shown) are comprised in a light source module (not shown) of the optical measurement apparatus  40 . The light array  42  could be composed of a plurality of LEDs or a plurality of OLEDs to provide a spontaneous emission light.  
      Because the cost of LED is far lower than the cost of a laser system, a large amount of LEDs could be used to compose the light array  42  of desired light intensity for scanning a test sample  46 . The LEDs of the light array  42  could also be exchanged for providing the desired wavelength for illuminating the test sample  46 . Different from a laser system of continuous excitation light, the light array  42  of LEDs could be switched swiftly for the linear charge coupled device  54  to detect an image signal. Further, the utilization of light array  42  of LEDs could simplify the operation for filtering noises of a laser system.  
      An excitation filter (not shown) could be arranged in the optical measurement apparatus  40  for filtering the spontaneous emission light, configured between the light array  42  and the arc-line-type wedge-shaped light-guiding apparatus  44 . Besides, a light-mending lens (not shown) could also be arranged in the optical path of the light array  42  to enhance the quality of the spontaneous emission light, and the material of the light-mending lens could be selected from the group consisting of glass, acrylics, and polycarbonate.  
      The arc-line-type wedge-shaped light-guiding apparatus  44  is configured between the light array  42  and the test sample  46 . Hence, an area of spontaneous emission light, emitted from the light array  42  of the light source module, is transformed into a linear light and be projected into the test sample  46  by the arc-line-type wedge-shaped light-guiding apparatus  44 . The test sample  46  is arranged to place on a detection area (not shown) of a platform  47 , and the platform  47  is used to support and transport the test sample  46  moving in one-dimension. In addition, the linear light will pass through the detection area when the test sample  46  is not available on the platform  47 .  
      In this embodiment, the optical measurement apparatus  40  is also provided with a light-mending lens  45 , configured between the arc-line-type wedge-shaped light-guiding apparatus  44  and the test sample  46  for trimming the light distribution of the spontaneous emission light, and the material of the light-mending lens  45  could be selected from the group consisting of glass, acrylics, and polycarbonate. Moreover, the optical measurement apparatus  40  could also comprise another excitation filter (not shown), configured between the arc-line-type wedge-shaped light-guiding apparatus  44  and the test sample  46  for filtering the spontaneous emission light and enhancing the quality of light. The excitation filter could also be configured between the arc-line-type wedge-shaped light-guiding apparatus  44  and the light array  42 .  
      The test sample  46  could be selected from the array-type samples such as microarray sample, gene chip, protein chip, or ELISA-based biochip (enzyme-linked immunoabsorbent assay). And the optical characteristics produced from the test sample  46  could be transformed and detected by an imaging module and an image-sensing module of the optical measurement apparatus  40  as below description.  
      After the linear spontaneous emission light illuminates on the test sample  46 , an emission light  48  is produced. Reflected and imaged by an emission error  50  and a linear charge couple device  54 , the emission light  48  will finally be detected by a linear charge coupled device  54 . In this embodiment, the emission mirror  50  and the focusing lens  52  are comprised in an image module (not shown). Besides, a micro diffraction grating  51  and a projection lens  53  are provided in the image module to trim the distribution of the emission light  48  and to project it into the linear charge coupled device  54 .  
      An image-sensing module (not shown), comprising the linear charge coupled device  54  and its control unit (not shown), is arranged for detecting and processing the emission light  48 . The image-sensing module could also comprise a filter lens and a dichroic mirror for achieving special functions. Furthermore, the image module and the image-sensing module could be integrated into a receiving module for receiving and processing the emission light  48  from the test sample  46 . The linear charge coupled device  54  could also be replaced by an area charge coupled device or a complementary metal-oxide field effect transistor (MOSFET) sensor for detection the area light.  
      Because the arc-line-type wedge-shaped light-guiding apparatus  44  is arranged in the optical measurement apparatus  40  of this preferred embodiment, the space occupied by the optical measurement apparatus  40  could be minified. Besides, the arc-line-type wedge-shaped light-guiding apparatus  44  takes advantage of the full reflection of light to guide incident area excitation light to be linear excitation light of high luminous flux and extreme small area. Hence, when the test sample  46  is scanned, the platform  47 , used to support the test sample  46 , has only to move in one-dimensionally to proceed scanning. The one-dimensional motion of the platform  47  could be achieved by a reduction gear and driven from a stepping motor. This design of this preferred embodiment would not only save the space occupied by the optical measurement apparatus  40 , but also simplify the complexity of the mechanism and save time for scanning the test sample  46 . Further, the design of this optical measurement apparatus  40  will reduce overall processing cost for detecting an array-type sample.  
      Another preferred embodiment of the present invention is as shown in  FIG. 4 , an optical measurement apparatus  60 , with piercing formation of image, is provided with a light array  62 , an straight-line-type wedge-shaped light-guiding apparatus  64 , a light mending module  66 , a platform  69 , a focusing lens  72 , and a linear charge coupled device (CCD)  74 . The light array  62  could be made up of a plurality of LEDs or a plurality of OLEDs. Because the cost of LED is far lower than the cost of a laser system, a large amount of LEDs could be used to compose the light array  62  of desired light intensity for scanning a test sample  68 . The LEDs of the light array  62  could also be exchanged for providing a light with a desired wavelength. Different from a laser system of continuous excitation light, the light array  62  of LEDs could be switched swiftly for the linear charge coupled device  74  to have a correct detection. Utilizing the light array  62  of LEDs will reduces the operation for filtering noises of the conventional light source such as laser system.  
      In the operation of the optical measurement apparatus  60 , first, an area spontaneous emission light  70  is emitted from the light array  62  and is then transformed as a linear light through the straight-line-type wedge-shaped light-guiding apparatus  64 . Then the light-mending module  66 , configured between the straight-line-type wedge-shaped light-guiding apparatus  64  and a test sample  68 , is arranged to make the linear light with a uniform distribution.  
      After the linear spontaneous emission light  70  illuminates the test sample  68 , an emission light  71  is produced, and the focusing lens  72  will transfer the emission light  71  to the linear charge coupled device  74 . In addition, before the emission light  71  passes through the focusing lens  72 , an excitation filter  75  and a micro diffraction grating  76  are arranged to filter out the excitation light and to trim the distribution of the emission light  71 . According to the present invention, the linear charge coupled device  74  could be replaced by an area charge coupled device or a complementary metal-oxide field effect transistor (MOSFET) sensor for detection area light.  
      The above description of the preferred embodiments will not be used to limit the claims of the present invention; any change of equal effect or modifications that do not depart from the essence displayed by the invention should be limited in what is claimed in the following.