Display device and method for manufacturing the same

Abstract

To provide an input device including a display screen which has an image display function and a text information input function by using a display portion in which a pixel includes an optical sensor. An optical sensor is provided in each pixel of the display portion in order to detect position information. A transistor of a pixel circuit in the display portion and the optical sensor are formed using a single crystal semiconductor layer. By using the single crystal semiconductor layer, there is no variation in characteristics among pixels, and position detection with high accuracy is realized. Moreover, the display portion is formed using a substrate which is a light-transmitting substrate such as a glass substrate provided with a single crystal semiconductor layer separated from a single crystal semiconductor substrate.

1 . A display device comprising:
 a display portion including a plurality of pixels;   a pixel circuit provided in each of the plurality of pixels, the pixel circuit comprising a first transistor and a display element;   a sensor circuit provided in a part of the plurality of pixels, the sensor circuit including an optical sensor and a second transistor;   a pixel driver circuit electrically connected to the pixel circuit, the pixel driver circuit comprising a third transistor; and   a sensor driver circuit electrically connected to the sensor circuit, the sensor driver circuit comprising a fourth transistor,   wherein the pixel circuit, the sensor circuit, the pixel driver circuit, and the sensor driver circuit are formed over a substrate, and   wherein each of the first, second, third and fourth transistors comprises a single crystal semiconductor layer.   
   
   
       2 . The display device according to  claim 1 , wherein the substrate is a light-transmitting substrate. 
   
   
       3 . The display device according to  claim 1 , further comprising a photoelectric conversion layer of the optical sensor formed using a single crystal semiconductor layer. 
   
   
       4 . The display device according to  claim 1 , wherein the display element is a liquid crystal element. 
   
   
       5 . The display device according to  claim 1 , wherein the display element is a light-emitting element. 
   
   
       6 . The display device according to  claim 1 , further comprising a display switching circuit electrically connected to the sensor driver circuit and the pixel driver circuit. 
   
   
       7 . The display device according to  claim 6 , wherein a detection signal of the optical sensor is input to the sensor driver circuit and the sensor driver circuit outputs the detection signal to the display switching circuit, and wherein the display switching circuit outputs a signal for switching display of the display portion to the pixel driver circuit, based on the detection signal input from the sensor driver circuit. 
   
   
       8 . The display device according to  claim 1 , further comprising a backlight unit including a plurality of light-emitting diodes and illuminating the display portion. 
   
   
       9 . The display device according to  claim 8 , wherein the backlight unit includes a light-emitting diode having a light emission spectrum with a peak at a wavelength of 800 nm to 1 μm. 
   
   
       10 . A display device comprising:
 a display portion including a plurality of pixels;   a pixel circuit provided in each of the plurality of pixels, the pixel circuit comprising a first transistor and a display element;   a sensor circuit provided in each of the plurality of pixels, the sensor circuit including an optical sensor and a second transistor;   a pixel driver circuit electrically connected to the pixel circuit, the pixel driver circuit comprising a third transistor; and   a sensor driver circuit electrically connected to the sensor circuit, the sensor driver circuit comprising a fourth transistor,   wherein the pixel circuit, the sensor circuit, the pixel driver circuit, and the sensor driver circuit are formed over a substrate, and   wherein each of the first, second, third and fourth transistors comprises a single crystal semiconductor layer.   
   
   
       11 . The display device according to  claim 10 , wherein the substrate is a light-transmitting substrate. 
   
   
       12 . The display device according to  claim 10 , further comprising a photoelectric conversion layer of the optical sensor formed using a single crystal semiconductor layer. 
   
   
       13 . The display device according to  claim 10 , wherein the display element is a liquid crystal element. 
   
   
       14 . The display device according to  claim 10 , wherein the display element is a light-emitting element. 
   
   
       15 . The display device according to  claim 10 , further comprising a display switching circuit electrically connected to the sensor driver circuit and the pixel driver circuit. 
   
   
       16 . The display device according to  claim 15 , wherein a detection signal of the optical sensor is input to the sensor driver circuit and the sensor driver circuit outputs the detection signal to the display switching circuit, and wherein the display switching circuit outputs a signal for switching display of the display portion to the pixel driver circuit, based on the detection signal input from the sensor driver circuit. 
   
   
       17 . The display device according to  claim 10 , further comprising a backlight unit including a plurality of light-emitting diodes and illuminating the display portion. 
   
   
       18 . The display device according to  claim 17 , wherein the backlight unit includes a light-emitting diode having a light emission spectrum with a peak at a wavelength of 800 nm to 1 μm. 
   
   
       19 . A display device comprising:
 a display portion including a pixel;   a pixel circuit provided in the pixel, the pixel circuit comprising a first transistor and a display element;   a sensor circuit provided in the pixel, the sensor circuit including an optical sensor and a second transistor;   a pixel driver circuit electrically connected to the pixel circuit, the pixel driver circuit comprising a third transistor; and   a sensor driver circuit electrically connected to the sensor circuit, the sensor driver circuit comprising a fourth transistor,   wherein the pixel circuit, the sensor circuit, the pixel driver circuit, and the sensor driver circuit are formed over a substrate, and   wherein each of the first, second, third and fourth transistors comprises a single crystal semiconductor layer.   
   
   
       20 . The display device according to  claim 19 , wherein the substrate is a light-transmitting substrate. 
   
   
       21 . The display device according to  claim 19 , further comprising a photoelectric conversion layer of the optical sensor formed using a single crystal semiconductor layer. 
   
   
       22 . The display device according to  claim 19 , wherein the display element is a liquid crystal element. 
   
   
       23 . The display device according to  claim 19 , wherein the display element is a light-emitting element. 
   
   
       24 . A method for manufacturing a display device including a display portion including a plurality of pixels; a pixel circuit provided in each of the plurality of pixels and including a display element and a first transistor; a sensor circuit provided in all or part of the plurality of pixels and including an optical sensor and a second transistor; a pixel driver circuit electrically connected to the pixel circuit; and a sensor driver circuit electrically connected to the sensor circuit, comprising the steps of:
 preparing a single crystal semiconductor substrate and a supporting substrate;   forming a damaged region in a region at a predetermined depth from a surface of the single crystal semiconductor substrate by adding an accelerated ion to the single crystal semiconductor substrate;   forming a buffer layer over at least one of the supporting substrate and the single crystal semiconductor substrate;   fixing the single crystal semiconductor substrate to the supporting substrate by disposing the supporting substrate and the single crystal semiconductor substrate in contact with each other with the buffer layer therebetween so that a surface of the buffer layer and a surface disposed in contact with the surface of the buffer layer are bonded to each other;   forming the supporting substrate to which a single crystal semiconductor layer separated from the single crystal semiconductor substrate is fixed, by generating a crack in the damaged region by heating of the single crystal semiconductor substrate so that the single crystal semiconductor substrate is separated from the supporting substrate;   forming a plurality of single crystal semiconductor layers by dividing the single crystal semiconductor layer among elements; and   forming the transistors in the pixel circuit and the sensor circuit, the transistors in the pixel driver circuit and the sensor driver circuit, and the optical sensor using the divided single crystal semiconductor layer.   
   
   
       25 . The method for manufacturing the display device according to  claim 24 , wherein the display element is a liquid crystal element. 
   
   
       26 . The method for manufacturing the display device according to  claim 24 , wherein the display element is a light-emitting element.