Use of light transmission through tissue to sense joint flexure

Abstract

Various embodiments relate to apparatuses and methods of using light transmission thought living tissue, such as a finger, to detect the flexure of a joint. Light is introduced into the tissue at one point, passes through the tissue, and exits the tissue at a second point where a sensor receives the light as it exits the tissue. Transmission of light through living tissue such as a finger can be affected by movement of the finger. As the finger flexes and, for example, the joints of the finger change angle, the characteristics of the light exiting the tissue, such as the intensity of the light, can change. These changes in characteristics can be used as an indirect means of determining the flexure of the joint.

What is claimed is: 
     
         1 . An apparatus for determining flexure of a joint in tissue comprising:
 a light source configured to introduce light into said tissue proximate to the joint;   a light sensing device configured to receive said light exiting said tissue proximate to the joint; and   a processing device configured to:   determine a characteristic of said received light exiting said tissue, and   determine said flexure of said joint based on the characteristic of said received light exiting said tissue.   
     
     
         2 . The apparatus of  claim 1 , wherein the characteristic relates to a change in optical density of said received light resulting from said flexure of said joint. 
     
     
         3 . The apparatus of  claim 1 , further comprising:
 a first optical fiber configured to send said light from said light source to a point of introduction of said light into said tissue; and   a second optical fiber configured to send said light from a point of exit of said light from said tissue to said light sensing device.   
     
     
         4 . The apparatus of  claim 3 , further comprising:
 a supporting object configured to provide mechanical support for at least a portion of said apparatus.   
     
     
         5 . The apparatus of  claim 4 , wherein said supporting object is a glove configured to be worn by a human hand, wherein said tissue comprises said human hand, and wherein said portion of said apparatus for which said glove provides said mechanical support is at least said first optical fiber and said second optical fiber. 
     
     
         6 . The apparatus of  claim 1 , wherein said light source is configured to be located at a point of introduction of said light into said tissue, and wherein said light sensing device is configured to be located at a point of exit of said light from said tissue. 
     
     
         7 . The apparatus of  claim 1 , further comprising:
 a supporting object that is a glove configured to be worn by a human hand, wherein said tissue comprises said human hand, and wherein said portion of said apparatus for which said glove is configured to provide mechanical support that is at least said light source and said light sensing device.   
     
     
         8 . The apparatus of  claim 7 , further comprising:
 a supporting object that is a body suit configured to be worn by a human, and wherein said tissue comprises the body of said human.   
     
     
         9 . The apparatus of  claim 1 , wherein the characteristic includes an intensity of said light after exiting said tissue. 
     
     
         10 . The apparatus of  claim 1 , wherein said light source generates infrared-spectrum light, and wherein said light sensing device receives infrared-spectrum light. 
     
     
         11 . The apparatus of  claim 1 , wherein said light source is an infrared-spectrum light-emitting diode (LED). 
     
     
         12 . The apparatus of  claim 1 , wherein said configuration of said processing device to determine said flexure further includes configuration to determine an angle of said joint. 
     
     
         13 . A processor circuit configured to determine a first characteristic of light exiting tissue proximate to a joint, and configured to determine a first position of the joint based on the first characteristics of the light exiting the tissue proximate to the joint. 
     
     
         14 . The processor circuit of  claim 13 , wherein the first characteristic of the light includes an intensity of the light exiting the tissue proximate to the joint. 
     
     
         15 . The processor circuit of  claim 13 , wherein the first characteristic of the light includes a first light intensity, and the processor is configured to determine a second characteristic of light exiting the tissue including a second light intensity, the first light intensity corresponding to the first position, and the second light intensity corresponding to a second position of the joint, the first position and the second position being different. 
     
     
         16 . The processor circuit of  claim 15 , wherein the characteristics relates to a change in optical density of the light. 
     
     
         17 . A method, comprising,
 introducing first light into tissue proximate to a joint;   receiving second light related to the first light exiting the tissue proximate to the joint;   determining a characteristic of the second light; and   determining a flexure of the joint based on the characteristic of the second light.   
     
     
         18 . The method of  claim 17 , wherein the characteristic of the second light includes a change in optical density between the second light and the first light. 
     
     
         19 . The method of  claim 17 , wherein the characteristic of the second light includes light intensity of the second light. 
     
     
         20 . The method of  claim 17 , wherein determining the flexure includes determining an angle of the joint.