In-plane switching type liquid crystal display device

Abstract

A liquid crystal display device comprises a pair of substrates subjected to an aligning treatment in mutually parallel but opposite directions, a liquid crystal layer interposed between the pair of substrates, a first electrode bent into a “<” shape, and a second electrode formed via an insulating film with the first electrode. The first electrode comprises one linear section and another linear section that extend in directions that intersect the alignment treatment direction at different angles, a bent section that is provided at each end where the one linear section and the other linear section adjacent to each other and that extends in a direction that intersects the alignment treatment direction at an angle that is greater than each of the intersecting angles of the one linear section and the other linear section and the alignment treatment direction with respect to the alignment treatment directions.

1 . A liquid crystal display device comprising:
 a pair of substrates arranged opposite each other at a predetermined gap, having been subjected to an aligning treatment in mutually parallel directions on each of the mutually opposed inner surfaces;   a liquid crystal layer interposed in the gap between the pair of substrates and arranged substantially in parallel with the surfaces of the substrates, with the long axis of the liquid crystal molecule in alignment with the direction of the aligning treatment;   a plurality of first electrodes provided on one of the mutually opposed inner surfaces of the pair of substrates, comprising, in each predetermined region for forming a single pixel, one linear section and another linear section that extend in directions that intersect the direction of the aligning treatment at different angles, a bent section that is provided at each end where the one linear section and the other linear section adjacent to each other, and that extends in a direction that intersects the direction of the aligning treatment at an angle greater than each of the intersecting angles of the one linear section and the other linear section and the aligning treatment direction with respect to the aligning treatment direction, and a connection section that connects these bent sections; and   a second electrode that is arranged in isolation from the first electrode on the inner surface of the one substrate, and that generates with the first electrode a transversal electric field that changes the orientation of the long axis of the liquid crystal molecule within a plane substantially parallel to the surfaces of the substrates.   
   
   
       2 . The liquid crystal display device according to  claim 1 , wherein the first electrode comprises a plurality of linear sections long and narrow in shape which are formed in parallel at a distance from each other, and at least either one of one and the other linear sections in each pixel are connected to each other at least one of ends thereof. 
   
   
       3 . The liquid crystal display device according to  claim 1 , wherein a plurality of slits for forming the plurality of linear sections is formed on a transparent conductive film having an area corresponding to a predetermined region for forming a single pixel, and the first electrode is formed from a transparent conductive film other than the transparent conductive film removed as a result of the plurality of slits. 
   
   
       4 . The liquid crystal display device according to  claim 1 , wherein the first electrode forms two regions for aligning the orientation of the long axes of the liquid crystal molecules in two different orientations, a first orientation and a second orientation, when an electric field is applied between the first electrode and the second electrode, and one linear section of the first electrode is formed in one of these two regions, and the other linear section of the first electrode is formed in the other of the two regions. 
   
   
       5 . The liquid crystal display device according to  claim 1 , wherein the second electrode is arranged between the first electrode and the one substrate. 
   
   
       6 . The liquid crystal display device according to  claim 1 , wherein a side border of a connection section of the first electrode is formed into a continuous curved fringe. 
   
   
       7 . The liquid crystal display device according to  claim 1 , wherein, given an incline angle θa of one linear section and another linear section of the first electrode with respect to an aligning treatment direction, and an incline angle θb of the respective bent sections provided at the ends of the two adjacent linear sections with respect to the aligning treatment direction, the incline angle θa of the linear sections and the incline angle θb of the bent sections are set to:
   0°<θa<20°     20°<θb<40°   
   
   
       8 . The liquid crystal display device according to  claim 1 , wherein, given a length La of one linear section and another linear section of the first electrode, and a length Lb of the bent section, the two lengths La and Lb are set so that:
   La>nLb (n: 3 to 5)     10Lb>La>4Lb.   
   
   
       9 . The liquid crystal display device according to  claim 1 , wherein the first electrode forms an end bent section that is provided on at least the end of either one linear section or the other linear section, connected to the linear section, on the side opposite the side where the ends adjacent to each other, and that extends in a direction that intersects the direction of the aligning treatment at an angle greater than each of the intersecting angles of the one linear section and the other linear section and the aligning treatment direction with respect to the aligning treatment direction. 
   
   
       10 . The liquid crystal display device according to  claim 9 , wherein, given an incline angle θc of an end bent section with respect to an aligning treatment direction, the incline angle θc is set to:
 20°<θc<40°   
   
   
       11 . The liquid crystal display device according to  claim 10  wherein, given a length La of the linear section and a length Lc of the end bent section, the length Lc of the end bent section is set to:
   La>nLc (n: 3 to 5)     10Lc>La>4Lc.