Patent Publication Number: US-2018031902-A1

Title: Electro-optical device and electronic apparatus

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to an electro-optical device and an electronic apparatus. 
     2. Related Art 
     In an electro-optical device that is provided with a liquid crystal electro-optical panel and the like, the processing load of a driving circuit (driving IC) that drives the electro-optical panel increases in accordance with an increase and the like of the number of pixels. Thereby, it is possible to cause the heat that is generated by the driving circuit to increase. In contrast, JP-A-2010-102219 describes fixing the driving circuit on a flexible substrate to a heat dissipation member with a configuration in which the flexible substrates are connected to the respective terminal of each row of a plurality of rows. JP-A-2009-75457 describes disposing the heat dissipation member so as to overlap an integrated circuit on a wiring board. 
     In the technology in JP-A-2010-102219, a plurality of flexible substrates almost entirely overlap each other and also overlap the driving circuit. Therefore, dissipation of heat that is generated by the driving circuit on one flexible substrate tends to be hindered by another flexible substrate, and dissipation of heat is not sufficient due to the increased load on the driving circuit. JP-A-2009-75457 does not describe connecting a plurality of wiring boards to an electro-optical panel. 
     SUMMARY 
     An advantage of some aspects of the invention is to provide a technology for effectively dissipating heat that is generated by the driving circuit which is provided on each wiring board of the plurality of wiring boards. 
     According to an aspect of the invention, there is provided an electro-optical device including an electro-optical panel, a first wiring board, one end of which is connected to the electro-optical panel, a second wiring board, one end of which is connected to the electro-optical panel at a position in a first direction from the one end of the first wiring board and which is shaped to be bent in a second direction that is different from the first direction, a first driving circuit that is provided on the first wiring board and drives the electro-optical panel, and a second driving circuit that is provided in a bent part of the second wiring board and drives the electro-optical panel. 
     In the electro-optical device of the aspect of the invention, the second wiring board has one end which is positioned on a side in a first direction from the one end of the first wiring board, and a part bent in a second direction that is different from the first direction. The driving circuit of the second wiring board is provided in the bent part. Consequently, according to the aspect of the invention, the heat that is generated by the driving circuit is able to be effectively dissipated. 
     In the aspect of the invention, a heat dissipation member that is disposed at a position which covers the first driving circuit and the second driving circuit may be provided. 
     According to the aspect of the invention, it is possible to facilitate dissipation of heat from a first driving circuit and a second driving circuit by using the heat dissipation member. 
     In the aspect of the invention, the heat dissipation member may be disposed at a position which covers the first driving circuit and the second driving circuit from one surface side and the other surface side of the first wiring board and the second wiring board. 
     According to the aspect of the invention, it is possible to further facilitate dissipation of heat from the first driving circuit and the second driving circuit by using the heat dissipation member that is disposed on the one surface side and the other surface side of the first wiring board and the second wiring board. 
     In the aspect of the invention, there may be provided a third driving circuit that is provided at a position not overlapping the first driving circuit on the first wiring board and that drives the electro-optical panel and a fourth driving circuit that is provided at a position not overlapping the second driving circuit on the bent part and that drives the electro-optical panel. 
     According to the aspect of the invention, dissipation of heat that is generated by each driving circuit is efficient compared with a case in which the first wiring board, the second wiring board, the third wiring board, and the fourth wiring board overlap each other and the driving circuits that are provided on the wiring boards overlap each other. 
     The aspect of the invention is able to be conceived as an electronic apparatus other than the electro-optical device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a perspective view illustrating a configuration of an electro-optical device according to a first embodiment of the invention. 
         FIG. 2  shows a front surface view and a rear surface view of the electro-optical device according to the embodiment. 
         FIG. 3  is a front surface view of a liquid crystal panel according to the embodiment. 
         FIG. 4  is a diagram illustrating the liquid crystal panel in a state in which a second wiring board is connected according to the embodiment. 
         FIG. 5  is a diagram illustrating the liquid crystal panel in a state in which a first wiring board and the second wiring board are connected according to the embodiment. 
         FIG. 6  is a sectional view (sectional view VI-VI in  FIG. 1 ) when the electro-optical device is cut away along an X-axis according to the embodiment. 
         FIG. 7  is a perspective view illustrating a configuration of an electro-optical device according to a second embodiment of the invention. 
         FIG. 8  shows a front surface view and a rear surface view of the electro-optical device according to the embodiment. 
         FIG. 9  is a front surface view of a liquid crystal panel according to the embodiment. 
         FIG. 10  is a diagram illustrating the liquid crystal panel in a state in which a fourth wiring board is connected according to the embodiment. 
         FIG. 11  is a diagram illustrating the liquid crystal panel in a state in which a third wiring board is connected according to the embodiment. 
         FIG. 12  is a diagram illustrating the liquid crystal panel in a state in which a second wiring board is connected according to the embodiment. 
         FIG. 13  is a diagram illustrating the liquid crystal panel in a state in which a first wiring board is connected according to the embodiment. 
         FIG. 14  is a sectional view (sectional view XIV-XIV in  FIG. 7 ) when the electro-optical device is cut away along the X-axis according to the embodiment. 
         FIG. 15  is a front surface view of an electro-optical device according to a third embodiment of the invention. 
         FIG. 16  is a sectional view (sectional view XVI-XVI in  FIG. 15 ) when the electro-optical device is cut away along a Y-axis according to the embodiment. 
         FIG. 17  is a sectional view (sectional view XVII-XVII in  FIG. 15 ) when the electro-optical device is cut away along the Y-axis according to the embodiment. 
         FIG. 18  is a diagram illustrating a projector to which the electro-optical device of the invention is applied. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Embodiments of the invention will be described below with reference to the drawings. In each drawing referred to in the description below, the scale may be different from the actual scale in order for each member, each region, and the like to be recognizable sizes. 
     First Embodiment 
       FIG. 1  is a perspective view illustrating a configuration of an electro-optical device  1  according to a first embodiment.  FIG. 2  shows a front surface view and a rear surface view of the electro-optical device  1 . In the description below, each direction is represented using an orthogonal coordinate system that consists of an X-axis, a Y-axis, and a Z-axis indicated in  FIG. 1 . The X-axis and the Y-axis extend in a direction parallel to one side of a pixel region  200 , which has a rectangle shape. The Z-axis extends in a direction corresponding to a line of sight when viewing a liquid crystal panel  100  from a front surface. A direction from the front surface to a rear surface of the liquid crystal panel  100  is a positive Z-axis direction, and a direction from the rear surface to the front surface is a negative Z-axis direction. 
     The electro-optical device  1  is the liquid crystal display apparatus in the embodiment. The electro-optical device  1  is provided with the liquid crystal panel  100 , a casing  10 , a first wiring board  20 , a second wiring board  30 , and a heat dissipation member  300 . The liquid crystal panel  100  is accommodated in an open frame-shaped casing  10  in a display portion that corresponds to the pixel region  200  and is connected to one end of each of the first wiring board  20  and the second wiring board  30 . For example, the heat dissipation member  300  is formed using metal and has a shape that covers a part of the first wiring board  20  and the second wiring board  30 . The heat dissipation member  300  is provided in order to dissipate heat that is generated in the first wiring board  20  and the second wiring board  30 . The heat dissipation member  300  is configured to include a first heat dissipation member  310  that covers the first wiring board  20  and the second wiring board  30  from the front surface side and a second heat dissipation member  320  that covers the first wiring board  20  and the second wiring board  30  from the rear surface side. In addition, the heat dissipation member  300  is constituted to cover a first driving circuit  22  and a second driving circuit  32 , which are driving circuits described later. A plurality of fins  3101  for facilitating heat dissipation are disposed on a surface on the front surface side of the first heat dissipation member  310 , and a plurality of fins  3201  for facilitating heat dissipation are disposed on a surface on the rear surface side of the second heat dissipation member  320 . 
       FIG. 3  is a front surface view of the liquid crystal panel  100 . The liquid crystal panel  100  in a state in which the casing  10 , the first wiring board  20 , the second wiring board  30 , and the heat dissipation member  300  are removed is shown in  FIG. 3 . 
     The liquid crystal panel  100  is an example of an electro-optical panel that performs an electro-optical operation, and here, the liquid crystal panel  100  is a transmissive liquid crystal panel. The electro-optical operation includes a display operation that displays images in the pixel region  200 . The liquid crystal panel  100  is constituted such that an element substrate  111  on which a plurality of pixel electrodes (not shown) are formed and a counter substrate  112  on which a common electrode (not shown) is provided are pasted maintaining a fixed gap, and for example, in the gap, a vertical alignment (VA) type liquid crystal is disposed. Each of the element substrate  111  and the counter substrate  112  is formed by elements that have optical transparency, such as glass and quartz. 
     The pixel region  200  is formed on a surface of the element substrate  111  which faces the counter substrate  112 . Here, the pixel region  200  is a region that includes a plurality of pixels. Specifically, the pixel region  200  is formed by a plurality of pixel electrodes that are arranged in a matrix shape, and the pixel electrodes are disposed to correspond to each point of intersection of a scanning line of a plurality of rows that extend in the X-axis direction, which is equivalent to a row direction, and a data line of a plurality of columns that extend in the Y-axis direction, which is equivalent to a column direction. The Y-axis direction is equivalent to the first direction and the X-axis direction is equivalent to the second direction. A scanning line driving circuit  210  is provided along one side of a peripheral region of the pixel region  200  on the element substrate  111 , on the surface of the element substrate  111  which faces the counter substrate  112 . The scanning line of a plurality of rows of the pixel region  200  is connected to the scanning line driving circuit  210 . A data line selection circuit  220 , a first terminal group  120 , and a second terminal group  130  are formed on another side that is orthogonal to a side on which the scanning line driving circuit  210  is provided. The liquid crystal panel  100  of the embodiment is driven by two driving circuits consisting of the first driving circuit  22  and the second driving circuit  32  according to the number of data lines, as well as the capacity of a data line selection circuit  220  and the driving circuits. A driving signal which drives the liquid crystal panel  100  is supplied via the first terminal group  120  and the second terminal group  130 . The driving signal includes various signals or various voltages. The scanning line driving circuit  210  performs scanning line driving that supplies a scanning signal to each scanning line of a plurality of rows as an example of driving according to the signal and the voltage. In addition, the data line selection circuit  220  selects each data line of the plurality of columns and performs data line driving that supplies a data signal to pixels for displaying images in the pixel region  200  according to the data signal and a timing signal that are included in the driving signal. The liquid crystal panel  100  of the embodiment is able to drive double the number of data lines that are able to be driven by one driving circuit, and in addition, a compact high-definition liquid crystal panel  100  is configured without widening the size (width) of the liquid crystal panel  100  in the X-axis direction by disposing the first terminal group  120  and the second terminal group  130  in the Y-axis direction. Note that, in the following drawings, description of the data line selection circuit  220  and the scanning line driving circuit  210  is omitted. 
     The first terminal group  120  includes a plurality of first terminals  121  that are arranged in the X-axis direction. The first terminal group  120  is positioned further than the data line selection circuit  220  from the pixel region  200  and is separated from the pixel region  200 , and specifically, is positioned on the end portion of the element substrate  111  in the Y-axis direction. The plurality of first terminals  121  include a terminal to which the data signal and the timing signal are input, and are connected to the data line selection circuit  220 . At least the plurality of first terminals  121  to which the data signal is input are the same shape and have the same dimensions as in the embodiment and are rectangular when viewed in the Z-axis direction. In addition, at least the plurality of first terminals  121  to which the data signal is input are arranged at an equal pitch in the embodiment. 
     The second terminal group  130  includes a plurality of second terminals  131  that are arranged in the X-axis direction. The second terminal group  130  is positioned further than the first terminal group  120  from the pixel region  200  and is separated from the pixel region  200 , and specifically, is positioned further on the end portion of the element substrate  111  in the Y-axis direction than the first terminal group  120 . The plurality of second terminals  131  include a terminal to which the data signal and the timing signal are input, and are connected to the data line selection circuit  220 . At least the plurality of second terminals  131  to which the data signal is input are the same shape and have the same dimensions as in the embodiment and are rectangular when viewed in the Z-axis direction. In addition, at least the plurality of second terminals  131  to which the data signal is input are arranged at an equal pitch in the embodiment. In the embodiment, the first terminal group  120  and the second terminal group  130  have the same position in the X-axis direction as one set of the first terminal  121  and the second terminal  131 . 
     Note that, the number of terminals that are included in the first terminal group  120  and the second terminal group  130  is specified according to the number of data lines and the capacities of the data line selection circuit  220 , the first driving circuit  22 , and the second driving circuit  32 . 
     The first wiring board  20  is connected to the plurality of first terminals  121  of the first terminal group  120 , and the second wiring board  30  is connected to the plurality of second terminals  131  of the second terminal group  130 . During connection of the liquid crystal panel  100 , first, the second wiring board  30  is connected to the liquid crystal panel  100 , and then, the first wiring board  20  is connected to the liquid crystal panel  100 . The liquid crystal panel  100  in a state in which the second wiring board  30  is connected is indicated in  FIG. 4 . 
     As shown in  FIG. 4 , one end of the second wiring board  30  is disposed on the element substrate  111  of the liquid crystal panel  100  and is connected to a plurality of second terminals  131  of the second terminal group  130 . A driving signal which drives the liquid crystal panel  100  is supplied to the second terminal  131  via the second wiring board  30 . 
     The second wiring board  30  is provided with a base material  31  and a second driving circuit  32  that is provided on the rear surface side of the base material  31 . The base material  31  is a substrate that is formed by a deformable material (for example, a film substrate or a flexible substrate) and is a flexible print circuit (FPC) on which a plurality of wires that are not illustrated are formed. The base material  31  is constituted by a first portion  311  and a second portion  312 . The first portion  311  is a portion on which the element substrate  111  of the liquid crystal panel  100  is disposed and has a form in which the plurality of wires extend in the Y-axis direction. The second portion  312  is a portion of the base material  31  other than the first portion  311 . The second portion  312  includes a portion which is shaped to be bent in the X-axis direction from the Y-axis direction. 
     The second driving circuit  32  is an integrated circuit (driving IC) that generates and supplies the driving signal to the liquid crystal panel  100 . The second driving circuit  32  is electrically and mechanically disposed on a surface on the rear surface side of the second portion  312  of the base material  31  by using a tape automated bonding (TAB) technique, and at least some of the plurality of wires of the base material  31  are connected. The second driving circuit  32  is connected to an upper circuit that is not illustrated. The first driving circuit  22 , a third driving circuit  42 , and a fourth driving circuit  52  described later have an equal function to the second driving circuit  32  and drive the pixel region  200  that includes data lines of the liquid crystal panel  100  in a shared manner. 
     The liquid crystal panel  100  in a state in which the first wiring board  20  and the second wiring board  30  are connected is indicated in  FIG. 5 . As shown in  FIG. 5 , one end of the first wiring board  20  is disposed on the element substrate  111  to overlap the second wiring board  30  (here, the first portion  311 ) and is connected to the plurality of first terminals  121  of the first terminal group  120 . A driving signal which drives the liquid crystal panel  100  is supplied to the first terminal  121  via the first wiring board  20 . 
     The first wiring board  20  is provided with a base material  21  and a first driving circuit  22  that is provided on the rear surface side of the base material  21 . The configurations of the base material  21  and the first driving circuit  22  are substantially the same with respect to size as the respective base material  31  and the second driving circuit  32  of the second wiring board  30 . The base material  21  is constituted by a first portion  211  and a second portion  212 , and the first portion  211  is disposed on the element substrate  111  of the liquid crystal panel  100 , and the base material  21  has a shape which overlaps a part of the first portion  311  of the base material  31  of the second wiring board  30 . The second portion  212  is a part of the base material  21  other than the first portion  211  and is shaped to be bent in a direction different from the second portion  312  of the base material  31  of the second wiring board. In addition, the second portion  212  includes a part that does not overlap the second portion  312  of the base material  31  of the second wiring board. In the embodiment, the second portion  212  of the base material  21  and the second portion  312  of the base material  31  are formed symmetrically about a line in a state of being disposed on the liquid crystal panel  100 . The first driving circuit  22  is provided on a surface of the second portion  212 , which is on the rear surface side of the portion that does not overlap the second portion  312  of the base material  31  of the second wiring board  30 . Therefore, the first driving circuit  22  and the second driving circuit  32  are disposed aligned in the X-axis direction and have no overlap in the Z-axis direction. The heat dissipation member  300  is formed to cover the first driving circuit  22  and the second driving circuit  32 . 
       FIG. 6  is a sectional view (sectional view VI-VI in  FIG. 1 ) when the electro-optical device  1  is cut away along the X-axis. In the cut away part, the first driving circuit  22  is provided on the rear surface of the base material  21  and the second driving circuit  32  is provided on the rear surface of the base material  31 . As shown in  FIG. 6 , the surface on the front surface side of the base material  21  of the first wiring board  20  is fixed to the surface on the rear surface side of the first heat dissipation member  310  by using a fixing agent that has thermal conductivity (hereinafter, simply referred to as “fixing agent”). The fixing agent is, for example, an adhesive or grease. In addition, the surface on the rear surface side of the first driving circuit  22  is fixed to the surface on the front surface side of the second heat dissipation member  320  by using the fixing agent. In the same manner, the surface on the front surface side of the base material  31  of the second wiring board  30  is fixed to the surface on the rear surface side of the first heat dissipation member  310  by using the fixing agent. In addition, the surface on the rear surface side of the second driving circuit  32  is fixed to the surface on the front surface side of the second heat dissipation member  320  by using the fixing agent. 
     As shown in  FIG. 4 , the first driving circuit  22  and the second driving circuit  32  are disposed aligned in the X-axis direction and have no overlap in the Z-axis direction. Therefore, the first driving circuit  22  is formed to be covered by the heat dissipation member  300  in both directions of the positive Z-axis direction and the negative Z-axis direction. The first driving circuit  22  faces the second heat dissipation member  320  without interposing an object other than the fixing agent therebetween, and faces the first heat dissipation member  310  without interposing an object other than the base material  21  and the fixing agent therebetween. Therefore, dissipation of heat from the first driving circuit  22  tends not to be hindered by the base material  31  or the second driving circuit  32  of the second wiring board  30 , and as a result, it is possible for dissipation of heat of the first driving circuit  22  to be efficient. In the same manner, the second driving circuit  32  also faces the second heat dissipation member  320  without interposing an object other than the fixing agent therebetween, and faces the first heat dissipation member  310  without interposing an object other than the base material  31  and the fixing agent therebetween. Therefore, dissipation of heat from the second driving circuit  32  tends not to be hindered by the base material  21  or the first driving circuit  22  of the first wiring board  20 , and as a result, it is possible for dissipation of heat from the second driving circuit  32  to be efficient. 
     As described above, it is possible to effectively dissipate heat that is generated by each of the first driving circuit  22  on the first wiring board  20  and the second driving circuit  32  on the second wiring board  30 . 
     Second Embodiment 
     Next, a second embodiment of the invention will be described. A liquid crystal panel  100 A of the second embodiment has a small size and higher definition, for example, having two times the data lines of the liquid crystal panel  100  of the first embodiment (alternatively, two times the number of pixels). Four driving circuits with the same capacity as in the first embodiment are necessary to drive the liquid crystal panel  100 A. The second embodiment is different from the first embodiment described above in a point of the number of wiring boards that are connected to the liquid crystal panel being “4”. In the description below, the same reference numerals are given to the same elements as the first embodiment, “A” is given at the end of the reference numerals in the corresponding elements. 
       FIG. 7  is a perspective view illustrating a configuration of the electro-optical device  1 A according to the second embodiment.  FIG. 8  shows a front surface view and a rear surface view of the electro-optical device  1 A. The X-axis, the Y-axis, and the Z-axis are specified in the same manner as in the first embodiment described above. 
     The electro-optical device  1 A is provided with the liquid crystal panel  100 A, the casing  10 , the first wiring board  20 , the second wiring board  30 , a third wiring board  40 , a fourth wiring board  50 , and a heat dissipation member  300 A. The liquid crystal panel  100 A is connected to one end of each of the first wiring board  20 , the second wiring board  30 , the third wiring board  40 , and the fourth wiring board  50 . The dispositions of the first wiring board  20  and the second wiring board  30  are the same as in the first embodiment described above. The third wiring board  40  is disposed on the rear surface side of the first wiring board  20 . The fourth wiring board  50  is disposed on the rear surface side of the second wiring board  30 . 
     For example, the heat dissipation member  300 A is formed using metal, and has a shape that covers a part of the first wiring board  20 , the second wiring board  30 , the third wiring board  40 , and the fourth wiring board  50 . The heat dissipation member  300 A is provided in order to dissipate heat that is generated in the each wiring board. The heat dissipation member  300 A is configured to include a first heat dissipation member  310 A that covers each wiring board from the front surface side and a second heat dissipation member  320 A that covers each wiring board from the rear surface side. In addition, the heat dissipation member  300 A is constituted to cover the first driving circuit  22 , the second driving circuit  32 , the third driving circuit  42 , and the fourth driving circuit  52  that are described later. A plurality of fins  3101 A for facilitating heat dissipation are formed on a surface on the front surface side of the first heat dissipation member  310 A and a plurality of fins  3201 A for facilitating heat dissipation are formed on a surface on the rear surface side of the second heat dissipation member  320 A. 
       FIG. 9  is a front surface view of the liquid crystal panel  100 A. The liquid crystal panel  100 A in a state in which the casing  10 , the first wiring board  20 , the second wiring board  30 , the third wiring board  40 , the fourth wiring board  50 , and the heat dissipation member  300 A are removed is indicated in  FIG. 9 . 
     In addition to the first terminal group  120  and the second terminal group  130 , a third terminal group  140  and a fourth terminal group  150  are formed in the liquid crystal panel  100 A. 
     The third terminal group  140  includes a plurality of third terminals  141  that are arranged in the X-axis direction. The third terminal group  140  is positioned separated further from the pixel region  200  than the second terminal group  130 , and in detail, is positioned further on the end portion of the element substrate  111  in the Y-axis direction than the second terminal group  130 . The plurality of third terminals  141  include a terminal to which the data signal and the timing signal are input, and are connected to the data line selection circuit  220 . At least the plurality of third terminals  141  to which the data signal is input are the same shape and the same dimensions as in the embodiment, and are rectangular viewed in the Z-axis direction. In addition, at least the plurality of third terminals  141  to which the data signal is input are arranged at an equal pitch in the embodiment. 
     The fourth terminal group  150  includes a plurality of fourth terminals  151  that are arranged in the X-axis direction. The fourth terminal group  150  is positioned separated further from the pixel region  200  than the third terminal group  140 , and in detail, is positioned further on the end portion of the element substrate  111  in the Y-axis direction than the third terminal group  140 . The plurality of fourth terminals  151  include a terminal to which the data signal and the timing signal are input, and are connected to the data line selection circuit  220 . At least the plurality of fourth terminals  151  to which the data signal is input are the same shape and the same dimensions as in the embodiment, and are rectangular viewed in the Z-axis direction. In addition, at least the plurality of fourth terminals  151  to which the data signal is input are arranged at an equal pitch in the embodiment. 
     In the embodiment, the first terminal group  120 , the second terminal group  130 , the third terminal group  140 , and the fourth terminal group  150  have the same position in the X-axis direction as one set of the first terminal  121 , the second terminal  131 , the third terminal  141 , and the fourth terminal  151 . 
     Note that, the number of terminals that are included in the third terminal group  140  and the fourth terminal group  150  is specified according to the number of data lines and the capacity of the data line selection circuit  220 , and the first driving circuit  22  to the fourth driving circuit  52 . 
     The first wiring board  20  is connected to the plurality of first terminals  121  of the first terminal group  120 , the second wiring board  30  is connected to the plurality of second terminals  131  of the second terminal group  130 , the third wiring board  40  is connected to the plurality of third terminals  141  of the third terminal group  140 , and the fourth wiring board  50  is connected to the plurality of fourth terminals  151  of the fourth terminal group  150 . During connection of the liquid crystal panel  100 , the fourth wiring board  50 , the third wiring board  40 , the second wiring board  30 , and the first wiring board  20  are connected to the liquid crystal panel  100  in order. The liquid crystal panel  100 A in a state in which the fourth wiring board  50  is connected is indicated in  FIG. 10 . 
     As shown in  FIG. 10 , one end of the fourth wiring board  50  is disposed on the element substrate  111 , and is connected to the plurality of fourth terminals  151  of the fourth terminal group  150 . A driving signal which drives the liquid crystal panel  100 A is supplied to the fourth terminal  151  via the fourth wiring board  50 . 
     The fourth wiring board  50  is provided with the base material  51  and the fourth driving circuit  52  that is provided on the base material  51 . The configuration of the base material  51  and the fourth driving circuit  52  are substantially the same size as the respective base material  31  and the second driving circuit  32  of the second wiring board  30 . The base material  51  is constituted by a first portion  511  and a second portion  512 . The first portion  511  is a portion disposed on the element substrate  111  of the liquid crystal panel  100 A. The second portion  512  is a portion except for the first portion  511 . The second portion  512  includes a part with a shape that is bent in the X-axis direction from the Y-axis direction. The fourth driving circuit  52  is provided on a surface of the base material  51 , which is on the rear surface side of the second portion  512 . 
     The liquid crystal panel  100 A in a state in which the third wiring board  40  and the fourth wiring board  50  are connected is indicated in  FIG. 11 . 
     As shown in  FIG. 11 , one end of the third wiring board  40  is disposed on the element substrate  111  to overlap the fourth wiring board  50  (here, the first portion  511 ), and is connected to a plurality of third terminals  141  of the third terminal group  140 . A driving signal which drives the liquid crystal panel  100 A is supplied to the third terminal  141  via the third wiring board  40 . 
     The third wiring board  40  is provided with a base material  41  and a third driving circuit  42  that is provided on the rear surface side of the base material  41 . The configuration of the base material  41  and the third driving circuit  42  are substantially the same size as the respective base material  21  and the first driving circuit  22  of the first wiring board  20 . The base material  41  is constituted by a first portion  411  and a second portion  412 . The first portion  411  is disposed on the element substrate  111  of the liquid crystal panel  100 A, and overlaps a part of the first portion  511 . The second portion  412  is a portion except for the first portion  411 . The second portion  412  has a shape that is bent in the X-axis direction from the Y-axis direction. The third driving circuit  42  is provided on a surface of the base material  41 , which is on the rear surface side of the second portion  412 . Therefore, the third driving circuit  42  that is provided in the second portion  412  of the third wiring board  40  and the fourth driving circuit  52  that is provided in the second portion  512  of the fourth wiring board  50  are disposed lined up in the X-axis direction, and have no overlap in the Z-axis direction. 
     The liquid crystal panel  100 A in a state in which the second wiring board  30 , the third wiring board  40 , and the fourth wiring board  50  are connected is indicated in  FIG. 12 . The fourth wiring board  50  substantially overlaps the second wiring board  30 , therefore illustration is omitted in  FIG. 12 . As shown in  FIG. 12 , one end of the second wiring board  30  is disposed on the element substrate  111  to overlap a part of the third wiring board  40  (here first portion  411 ) and the fourth wiring board  50  (here first portion  511 ). Here, the second driving circuit  32  is provided on a surface on the rear surface side of the second portion  312  to overlap the fourth driving circuit  52  in the Z-axis direction. 
     The liquid crystal panel  100 A in a state in which the first wiring board  20 , the second wiring board  30 , the third wiring board  40 , and the fourth wiring board  50  are connected is indicated in  FIG. 13 . The third wiring board  40  and the fourth wiring board  50  each substantially overlap the first wiring board  20  and the second wiring board  30 , therefore illustration is omitted in  FIG. 13 . As shown in  FIG. 13 , one end of the first wiring board  20  is disposed on the element substrate  111  to overlap a part of the second wiring board  30  (here first portion  311 ), the third wiring board  40  (here first portion  411 ), and the fourth wiring board  50  (here first portion  511 ). Here, the first driving circuit  22  is provided on a surface on the rear surface side of the second portion  212  to overlap the third driving circuit  42  in the Z-axis direction. The heat dissipation member  300 A is formed to cover the first driving circuit  22 , the second driving circuit  32 , the third driving circuit  42 , and the fourth driving circuit  52 . 
       FIG. 14  is a sectional view (sectional view XIV-XIV in  FIG. 7 ) when the electro-optical device  1 A is cut away along the X-axis. In the cut away part, the first driving circuit  22  to the fourth driving circuit  52  are provided on the rear surface of each of the base material  21  to the base material  51 . As shown in  FIG. 14 , the base material  21  of the first wiring board  20  and the base material  31  of the second wiring board  30  are fixed to the surface on the rear surface side of the first heat dissipation member  310 A by using the fixing agent. However, the rear surface side of the first driving circuit  22  and the second driving circuit  32  is not respectively fixed. The third driving circuit  42  of the third wiring board  40  and the fourth driving circuit  52  of the fourth wiring board  50  are fixed to the surface on the front surface side of the second heat dissipation member  320 A by using the fixing agent. However, the front surface side of the base material  41  and the base material  51  is not respectively fixed. Therefore, a space (gap) is formed between the first driving circuit  22  and the base material  41  of the third wiring board  40 , and a space (gap) is formed between the second driving circuit  32  and the base material  51  of the fourth wiring board  50 . 
     As described already, the base material  21  of the first wiring board  20  and the base material  31  of the second wiring board  30  have shapes bent in directions that are different from each other, and the base material  41  of the third wiring board  40  and the base material  51  of the fourth wiring board  50  have shapes bent in directions that are different from each other. Therefore, the first driving circuit  22  and the second driving circuit  32  are disposed lined up in the X-axis direction. In addition, the third driving circuit  42  and the fourth driving circuit  52  are disposed lined up in the X-axis direction. Furthermore, a space is formed between the first driving circuit  22  and the base material  41  of the third wiring board  40 , a space is formed between the second driving circuit  32  and the base material  51  of the fourth wiring board  50 , and a path along which the dissipated heat moves is secured. Therefore, it is possible for dissipation of heat of each of the first driving circuit  22 , the second driving circuit  32 , the third driving circuit  42 , and the fourth driving circuit  52  to be efficient. 
     Third Embodiment 
     Next, a third embodiment of the invention will be described. In the third embodiment, a positional relationship of the first driving circuit  22  and the third driving circuit  42  and a positional relationship of the second driving circuit  32  and the fourth driving circuit  52  are different from the second embodiment described above. 
       FIG. 15  is a front surface view of the electro-optical device  1 A of the embodiment. In  FIG. 15 , a two-dot chain line indicates a region in which a heat dissipation member  300 A is present.  FIG. 16  is a sectional view (sectional view XVI-XVI in  FIG. 15 ) when the electro-optical device  1 A is cut away along the Y-axis on a plane that includes the first wiring board  20  and the third wiring board  40 .  FIG. 17  is a sectional view (sectional view XVII-XVII in  FIG. 15 ) when the electro-optical device  1 A is cut away along the Y-axis on a plane that includes the second wiring board  30  and the fourth wiring board  50 . 
     As shown in  FIGS. 15 and 16 , the first driving circuit  22  and the third driving circuit  42  do not overlap in the Z-axis direction with the position deviated in the Y-axis direction. In addition, as shown in  FIGS. 15 and 17 , the second driving circuit  32  and the fourth driving circuit  52  do not overlap in the Z-axis direction with the position deviated in the Y-axis direction. 
     Note that, the first driving circuit  22  and the second driving circuit  32  are disposed lined up in the X-axis direction in the same manner as in the second embodiment described above. In addition, the third driving circuit  42  and the fourth driving circuit  52  are disposed lined up in the X-axis direction in the same manner as in the second embodiment described above. 
     By disposing each driving circuit described in  FIGS. 15 to 17 , the rear surface side of the first driving circuit  22  faces the second heat dissipation member  320 A without interposing the third driving circuit  42 , and the front surface side of the third driving circuit  42  faces the first heat dissipation member  310 A without interposing the second driving circuit  32 . In addition, the rear surface side of the second driving circuit  32  faces the second heat dissipation member  320 A without interposing the fourth driving circuit  52 , and the front surface side of the fourth driving circuit  52  faces the first heat dissipation member  310 A without interposing the second driving circuit  32 . Thereby, the path along which the dissipated heat moves is more widely secured than in the configuration of the second embodiment described above. Consequently, it is possible for dissipation of heat of each of the first driving circuit  22 , the second driving circuit  32 , the third driving circuit  42 , and the fourth driving circuit  52  to be efficient. 
     Modification Example 
     The invention is able to be applied in an aspect different from the embodiment described above. In addition, the modification example indicated below may be appropriately combined with each embodiment. 
     In the embodiment described above, the first wiring board  20  to the fourth wiring board  50  that are connected to the liquid crystal panels  100  and  100 A are covered by a heat dissipation member from both sides of the front surface side and the rear surface side. Instead of this, the first wiring board  20  to the fourth wiring board  50  may be configured to be covered by the heat dissipation members  300  and  300 A from one side of the front surface side and the rear surface side. In addition, the heat dissipation members  300  and  300 A may adopt a configuration to cover at least one wiring board among the first wiring board  20  to the fourth wiring board  50 . In addition, the heat dissipation members  300  and  300 A may be integrally formed with the casing  10 . 
     In addition, the shapes of each wiring board (base material) are only examples. 
     In the invention, the terminal group on the element substrate is not limited to two or four, and three or five or more may be provided. In this case, the wiring boards are connected to terminal groups respectively. 
     The electro-optical panel of the invention may not be a transmissive liquid crystal panel, and for example, may be a reflective liquid crystal panel. In addition, the electro-optical panel of the invention may be a panel that uses an electro-optical element other than liquid crystal such as organic electro-luminescence (EL) if an electro-optical operation is performed. 
     Next, a projection-type display apparatus (projector) using the liquid crystal panel  100  as a light bulb is described as an example of an electronic apparatus that uses the electro-optical device  1  according to each embodiment described above.  FIG. 18  is a planar view illustrating a configuration of the projector. 
     As shown in  FIG. 18 , a lamp unit  2102  that consists of a white light source such as a halogen lamp is provided inside a projector  2100 . Projected light that is projected from the lamp unit  2102  is separated into three primary colors of R, G, and B using three mirrors  2106  and two dichroic mirrors  2108  that are disposed internally, and are respectively lead to light bulbs  100 R,  100 G, and  100 B that correspond to each primary color. Note that, when compared to R and G, B light has a long light path, therefore in order to prevent loss of light, the B light is led via a relay lens system  2121  that consists of an incident lens  2122 , a relay lens  2123 , and an emission lens  2124 . 
     In the projector  2100 , the electro-optical device  1  that includes the liquid crystal panel  100  to which at least the first wiring board  20  and the second wiring board  30  are connected is provided in three sets that respectively correspond to R, G, and B. The configuration of the light bulbs  100 R,  100 G, and  100 B is the same as the liquid crystal panel  100  described above. A video signal with respective primary color components of R, G, and B is supplied from respective external upper circuits via respective wiring boards, and the light bulbs  100 R,  100 G, and  100 B are configured to be respectively driven. In addition, the electro-optical device  1  is disposed on the projector  2100  such that it is possible to more effectively dissipate heat using the heat dissipation members  300  and  300 A. 
     Light that is respectively modulated by the light bulbs  100 R,  100 G, and  100 B is incident from three directions in a dichroic prism  2112 . Then, in the dichroic prism  2112 , R and B light is refracted at 90 degrees while G light goes straight. Accordingly, after an image of each primary color is synthesized, a color image is projected by a projection lens  2114  on a screen  2120 . 
     Note that, since light that respectively corresponds to R, G, and B is incident by the dichroic mirrors  2108  to the light bulbs  100 R,  100 G, and  100 B, it is not necessary to provide a color filter. In addition, there is a configuration in which since a transmission image of the light bulb  100 G is projected without any changes with respect to transmission images of the light bulbs  100 R and  100 B being projected after being reflected by the dichroic prism  2112 , a horizontal scanning direction by the light bulbs  100 R and  100 B is a reverse orientation to the horizontal scanning direction by the light bulb  100 G and an image that is reflected left and right is displayed. 
     Other than the projector that is described with reference to  FIG. 18 , a television, a view finder type/monitor direct view type video tape recorder, a car navigation device, a pager, an electronic diary, an electronic calculator, a word processor, a workstation, a video phone, a POS terminal, a digital still camera, a mobile phone, a smartphone, a tablet type terminal, another device that is provided with a touch panel, and the like are given as the electronic apparatus. Then, the electro-optical device  1  is able to be applied to the various electronic apparatus. 
     The entire disclosure of Japanese Patent Application No. 2016-146025, filed Jul. 26, 2016 is expressly incorporated by reference herein.