Abstract:
The disclosure is directed to flexible boards, electrooptic devices having flexible boards, and electronic devices. In one example, wires are disposed longitudinally along the length of a flexible board. Terminals are arranged laterally across the width of the flexible board near an end of the flexible board, the terminals being electrically connected to the wires. Plating lead wires are electrically connected to the terminals and extend longitudinally from the terminals to a lateral edge of the flexible board. The width of the plating lead wires is less than the width of the wires. In certain embodiments, at least a portion of the terminals are alternatingly displaced on the flexible board in a staggered manner. This abstract is intended only to aid those searching patents, and is not intended to be used to interpret or limit the scope or meaning of the claims in any manner.

Description:
RELATED APPLICATION INFORMATION 
   The present application claims priority from Japanese Patent Application No. 2006-272647, filed on Oct. 4, 2006, the disclosure of which is hereby incorporated by reference in its entirety. 
   BACKGROUND 
   This disclosure relates to a flexible board that may be mounted to an electrooptic device such as a liquid crystal device, and an electronic device such as, for example, a liquid crystal projector, that includes such electrooptic device. 
   Various electronic devices such as projectors, portable phones, and mobile personal computers incorporate electrooptic devices such as liquid crystal devices. 
   Electrooptic devices and electronic devices are commonly connected in such a manner that a connector extending from the electrooptic device is connected to a flexible board, and the flexible board is connected to the connecting portion of the electronic device. The connector and the flexible board are commonly connected by inserting the end of the flexible board having the terminals of the wires into the connector. For example, Japanese Patent Application Laid-Open Publication No. 7-296941 proposes an insertion jig with which the operator can insert the end of the flexible board into the connector. 
   The flexible board may have plating lead wires for electroplating the terminals of the wires with gold for each terminal. 
   However, this method is problematic as the possibility exists of a short circuit between adjacent terminals by the plating lead wires if the end of the flexible board is inserted at an angle into the connector. This short circuit between the adjacent terminals may cause abnormal operation or problems with the device connected to the flexible board. 
   SUMMARY 
   In certain embodiments, a flexible board for making electrical connection to a connector has a plurality of wires disposed longitudinally along the length of the flexible board. A plurality of terminals are arranged laterally across the width of the flexible board near an end of the flexible board. The plurality of terminals are electrically connected to the wires. A plurality of plating lead wires are electrically connected to the terminals and extend longitudinally from the terminals to a lateral edge of the flexible board. The plating lead wires have a width that is less than the width of the wires. 
   The flexible board may be connected to the connector in such a manner that an end of the flexible board is fitted in the connection opening of the connector. In other words, the end of the flexible board is inserted into the connection opening of the connector so that the plurality of connection terminals in the connector are brought into contact with the plurality of terminals on the flexible board, electrically connecting the connector and the flexible board. The terminals may be arranged in a line or in a staggered manner along the width of the flexible board at one end of the flexible board. The connection terminals of the connector may also be arranged in a line or staggered manner in the opening of the connector. The flexible board is electrically connected to an electronic device such as a projector via the connector. The other end of the flexible board opposite of the connector is connected to an electrooptic device such as a liquid crystal device. 
   The flexible board may have a plurality of plating lead wires on the main body. The plurality of plating lead wires are used to apply a predetermined potential for plating the plurality of terminals with gold, gold plating, or the like to the plurality of terminals during the manufacture of the flexible board. The plating lead wires are generally not used during the operation of the device to which the flexible board is mounted. The plating lead wires may be connected to the portions of the terminals different from the portions connected to the wires, such as the portions opposite of the wires, and may extend along the length to an edge of the flexible board (for example, an edge adjacent to the end, that is, an edge along the width at the end). 
   In certain embodiments, the width of each plating lead wire is set smaller than the width of each wire. This can help reduce or prevent the short circuit (electrical shorting) between adjacent terminals that may otherwise occur when the flexible board is inserted at an angle into the connector. For example, if the plating lead wires and the wires are formed in such a manner that the width of each plating lead wire and the width of each wire are equal, without taking any additional measures, when the flexible board is inserted at an angle into the connector, a first plating lead wire and a second terminal adjacent to a first terminal connected to the first plating lead wire could potentially be short circuited by the connection terminal of the connector. The reason being that the connection terminal of the connector may come into contact with both the first plating lead wire and the second terminal, the first plating lead wire and the second terminal (i.e., the first terminal and the adjacent second terminal, in other words, the adjacent terminals) being electrically shorted. If a device connected to the flexible board is activated with the adjacent terminals short-circuited, an excessive current may flow into the device and interfere with normal operation or cause failure due to heat. 
   However, as described above, in certain embodiments the width of each plating lead wire is set smaller than the width of each wire. Accordingly, the distance between the first plating lead wire and the second terminal adjacent to the first terminal electrically connected to the first plating lead wires, or the distance between adjacent plating lead wires may be larger in comparison to when the width of each plating lead wire and the width of each wire are equal. This can be effective in helping prevent the contact of the connection terminal of the connector with both the first plating lead wire and the second terminal, or helping reduce or prevent the occurrence of a short circuit between adjacent terminals. This may also help reduce or prevent an abnormal operation or failure of a device connected to the flexible board due to a short circuit between the adjacent terminals. 
   The use of the flexible board according to certain embodiments may help reduce or prevent the occurrence of a short circuit between adjacent terminals because the width of each plating lead wire may be smaller than the width of each wire. 
   In certain embodiments, at least part of the plurality of terminals of the flexible board is arranged in a staggered manner. 
   For example, at least part of the terminals may be arranged in a staggered manner (alternately displaced in the longitudinal direction) along the width. This may help reduce the distance between adjacent terminals of the plurality of terminals, or may help the terminals be arranged with a narrow pitch as compared with a when the terminals are arranged in a line along the width. This can help the terminals (and the wires) be arranged in a highly dense manner on the flexible board, or help reduce the size of the flexible board. Furthermore, since the width of each plating lead wire may be set smaller than that of each wire, the occurrence of the short circuit between adjacent terminals can be reduced or prevented. Thus, the array pitch of the terminals may be decreased while helping reduce or prevent the occurrence of a short circuit between adjacent terminals. 
   In certain embodiments, end plating lead wires connected to the terminals at the ends of the array of the plurality of terminals extend along the width. 
   For example, the end plating lead wires extend from the terminals at the ends of the array of the terminals to the side edges of the flexible board along the width intersecting the longitudinal direction in which the other plating lead wires extend. Thus, in these embodiments, no plating lead wire is provided at the ends of the terminals disposed at the ends of the array of the terminals. This can help reduce or prevent the occurrence of a short circuit between the terminals at the ends of the array of the terminals and the adjacent terminals. 
   In certain embodiments, power-source-side terminals adjacent to power-source terminals to which supply potential is applied may be configured as dummy terminals in which no electric signal is input or output. 
   For example, the power-source-side terminals adjacent to the power-source terminals may be dummy terminals. Thus, even if the flexible board is inserted at an angle into the connector such as to generate a short circuit between the power-source terminals and the power-source-side terminals, potentially little or no negative influence, such as excess current or heat generation, is exerted on a device connected to the flexible board. 
   Generally, the power-source terminals are higher in potential than the other terminals to which other signals (for example, an image signal and various control signals) different from the supply potential are applied. Therefore, if the power-source terminals and the other terminals are short-circuited, trouble may occur in a device connected to the flexible board. Accordingly, in accordance with certain embodiments, the structure in which the power-source-side terminals adjacent to the power-source terminals are formed as dummy terminals can help reduce or prevent the occurrence of a short circuit between the power-source terminals and the other terminals to which other signals different from supply potential are applied, and thereby helping reduce or prevent trouble to the device connected to the flexible board. 
   The difference between the power-source-side terminals serving as dummy terminals and the other terminals is that no electric signal is input or output. Since no electric signal is applied to the power-source-side terminals serving as dummy terminals (although the structure is similar to the other terminals), they may not be connected to wires or plating lead wires. 
   In embodiments where the power-source-side terminals are configured as dummy terminals, as described above, the power-source-side terminals may not be connected to the plating lead wires. 
   Since the power-source-side terminals serve as dummy terminals in which no electric signals are input to or output from, they need not be plated. Therefore, no plating lead wires are provided to the power-source-side terminals. This helps reduce or prevent the occurrence of a short circuit between the power-source terminals and the power-source-side terminals. 
   According to certain embodiments, an electrooptic device includes a flexible board as described above. 
   Since the electrooptic device includes the above-described flexible board, the occurrence of a short circuit between adjacent terminals on the flexible board may be reduced or prevented. Therefore, an electrooptic device with higher reliability may be achieved. 
   According to certain embodiments, there is provided an electronic device including the electrooptic device as described above. 
   Since the electronic device has the above-described electrooptic device, the occurrence of a short circuit between adjacent terminals on the flexible board may be reduced or prevented. Therefore, various electronic devices may be achieved with higher reliability. Exemplary electronic devices include projection display devices, televisions, portable phones, electronic notebooks, word processors, viewfinder or monitor-direct-view type videotape recorders, workstations, TV phones, POS terminals, and touch panels. Other examples of electronic devices include electrophoresis devices such as electronic paper, field-emission displays and conduction electron-emitter displays, and display devices using such electrophoresis devices, field-emission displays and conduction electron-emitter displays. 
   Additional details and exemplary embodiments are disclosed below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Various embodiments are described with reference to the accompanying drawings, wherein like reference numbers designate like elements, and in which: 
       FIG. 1  illustrates a plan view of an exemplary flexible board and a connector. 
       FIG. 2  illustrates a cross sectional view of  FIG. 1 , taken along line II-II′. 
       FIG. 3  illustrates a plan view of an exemplary flexible board in a state in which it is inserted at an angle into the connector. 
       FIG. 4  illustrates a plan view of a comparative example in a state in which it is inserted at an angle into the connector 
       FIG. 5  illustrates a plan view of another exemplary flexible board in the same state as in  FIG. 1 . 
       FIG. 6  illustrates a plan view of yet another exemplary flexible board in the same state as in  FIG. 1 . 
       FIG. 7  illustrates a plan view of an exemplary liquid crystal device as an example of an electrooptic device. 
       FIG. 8  illustrates a cross-sectional view taken along line VIII-VIII′ of  FIG. 7 . 
       FIG. 9  illustrates a perspective view of an exemplary liquid crystal device with a flexible board as an example of an electrooptic device. 
       FIG. 10  illustrates a plan view of an exemplary projector as an example of an electronic device incorporating the electrooptic device. 
   

   DESCRIPTION OF EXEMPLARY EMBODIMENTS 
   Embodiments described herein will be best understood by reference to the drawings. It will be readily understood that the components generally described and illustrated in the drawings herein could be arranged and designed in a variety of configurations. Thus, the following description, as represented in the drawings, is not intended to limit the scope of the disclosure but is merely representative of certain embodiments. 
   A flexible board  200  according to certain embodiments will be described with reference to  FIGS. 1-4 . 
   Referring first to  FIGS. 1 and 2 , the configuration of the flexible board  200  will be described along with the configuration of a connector  300  connected to the flexible board.  FIG. 1  is a plan view of the entire configuration of the flexible board  200  and the connector  300 .  FIG. 2  is a cross sectional view of  FIG. 1 , taken along line II-II′.  FIG. 1  shows the flexible board  200  and the connector  300  in perspective, but does not show a cover  250  and a reinforcing plate  260  (see  FIG. 2 ). 
   In  FIGS. 1 and 2 , the flexible board  200  includes a main body  210 , a plurality of wires  220 , a plurality of terminals  230 , a plurality of plating lead wires  240 , the cover  250  (see  FIG. 2 ), and the reinforcing plate  260  (see  FIG. 2 ). 
   The main body  210  can be folded when mounting, and is made of resin film, plastic film or the like. 
   The wires  220  are placed on one surface of the main body  210 , and are made of electrically conductive and low-resistance metal film that can be folded with the main body  210  thereon. The plurality of wires  220  is provided in correspondence with the plurality of terminals  230  for connection with the connector  300 , and extends along the length of the flexible board  200  (vertically in  FIG. 1 ). 
   The terminals  230  are made of conductive metal. The terminals  230  are provided at one end of the flexible board  200  and connected to the wires  220 , respectively. The terminals  230  may be arranged in a staggered manner along the width of the flexible board  200 . For example, the terminals  230  may be arranged such that at least a portion of the adjacent terminals are alternatingly displaced along the length of the flexible board  200  (displaced vertically in  FIG. 1 ). The staggered arrangement of the terminals  230  can reduce the pitch between adjacent terminals  230  and thereby save space and reduce the size of the flexible board  200 . The contacts  321  of connection terminals  320  of the connector  300  are also arranged in a staggered manner at the opening  330  of the connector  300 . 
   The plating lead wires  240  may be connected to the ends of the terminals  230  opposite of the wires  220  (bottom portion of  FIG. 1 ) and extend to a lateral edge  200   e   1  of the flexible board  200  (extending vertically in  FIG. 1 ). The plating lead wires  240  may be made of either the same material as that of the wires  220  and the terminals  230  or of another conductive metal. 
   The cover  250  is foldable, and may be made of resin film or resist. The cover  250  covers the wires  220  except for the exposed portions of the wires  220 , such as the terminals  230  that come in contact with the contacts  321 . 
   The reinforcing plate  260  is made of resin or the like, and is bonded onto the surface of the main body  210  opposite to the wires  220 , at the end of the flexible board  200  next to the connector  300 . 
   The connector  300  includes a connector casing  310  made of a material such as resin or the like and the connection terminals  320  may be made of metal such as copper or aluminum. The flexible board  200  may be connected to the connector  300  by fitting an end  215  of the flexible board  200  with the connection opening  330  of the connector casing  310 . For example, the end  215  of the flexible board  200  may be inserted into the connection opening  330  of the connector casing  310  so that the contacts  321  of the connection terminals  320  of the connector  300  make electrical contact with the terminals  230 , and thus connecting together the connector  300  and the flexible board  200 . 
   The thickness of the end of the reinforcing plate  260  is adjusted to a thickness that allows connection with the connector  300  and allows the end  215  of the flexible board  200  to engage with the connector  300 . 
   Referring now to  FIGS. 3 and 4 , and with continued reference to  FIGS. 1 and 2 , the plating lead wires  240  of the flexible board  200  will be specifically described in accordance with certain embodiments.  FIG. 3  is a plan view of the flexible board  200  in a state in which it is inserted at an angle into the connector  300 .  FIG. 4  is a plan view of a comparative example in a similar state as shown in  FIG. 3 .  FIGS. 3 and 4  are illustrative of the parts of the flexible board and the connector related to a potential short circuit created between adjacent terminals, and for simplicity sake, omit the other elements shown in  FIG. 1 . 
   As shown in  FIGS. 1 and 3 , the width W 2  of each plating lead wire  240  may be set smaller than the width W 1  of each wire  220 . This can help reduce or help prevent a short circuit (electrical shorting) between adjacent terminals  230  that may occur when the flexible board  200  is inserted at an angle into the connector  300 . 
   Turning to  FIG. 4  as a comparative example, a flexible board  800  is configured such that a plurality of wires  820  and a plurality of plating lead wires  840  are disposed on a main body  810  in such a manner that the width W 3  of each wire  820  and the width W 4  of each plating lead wire  840  is substantially equal. If the flexible board  800  is inserted at an angle into the connector  300 , then a short circuit may be formed between a first plating lead wire  840   s  which is connected to a first terminal  830   s  and a second terminal  830   t  which is adjacent to the first terminal  830   s  by the contact  321  of the connector  300 . In other words, the contact  321  of the connector  300  may come into contact with both the first plating lead wire  840   s  and the second terminal  830   t  such that the first plating lead wire  840   s  and the second terminal  830   t  (that is, the adjacent terminals  830   s  and  830   t ) are electrically shorted. When a device connected to the flexible board  800  is activated with the adjacent terminals short-circuited, excessive current may flow into the device and interfere with normal operation or cause failure due to heat generation. 
   However, as depicted in  FIGS. 1 and 3 , in certain embodiments the width W 2  of each plating lead wire  240  may be set at a width smaller than the width W 1  of each wire  220 . Accordingly, the distance D 1  (see  FIG. 3 ) between the plating lead wire  240  and the adjacent terminal  230  and the distance D 2  (see  FIG. 3 ) between adjacent plating lead wires  240  is larger than if plating lead wires  840  and the wires  820  are formed such that the width W 4  of each plating lead wire  840  and the width W 3  of each wire  820  are substantially equal (as illustrated in  FIG. 4 ). In other words, with reference to  FIGS. 3 and 4 , the distance D 1  between the plating lead wire  240  and the adjacent terminal  230  is larger than the distance D 3  between the plating lead wire  840  and the adjacent terminal  830 , and the distance D 2  between adjacent plating lead wires  240  is larger than the distance D 4  between adjacent plating lead wires  840 . This can help in preventing the contacts  321  of the connector  300  from coming into contact with both the plating lead wires  240  and the terminals  230  when the flexible board  200  is inserted at an angle into the connector  300 . Accordingly, this can help reduce or prevent the occurrence of an electrical short circuit between the adjacent terminals  230  and can help reduce or prevent abnormal operation or failure of a device to which the flexible board  200  is connected due to such electrical short circuit. 
   As described above, the use of the flexible board  200  can help reduce or prevent the occurrence of a short circuit between the adjacent terminals  230  as the width W 2  of each plating lead wire  240  is smaller than the width W 1  of each wire  220 . 
   Referring next to  FIG. 5 , a flexible board  202  will be described in accordance with additional embodiments.  FIG. 5  is a plan view of the flexible board  202  in the same state as in  FIG. 1 . The connector  300  is omitted from  FIG. 5  because it has a similar configuration as that shown in  FIGS. 1-3 . Components of  FIG. 5  that are similar to those shown in  FIGS. 1-3  will be identified by the same reference numbers, and descriptions thereof will be omitted as deemed appropriate. 
   As shown in  FIG. 5 , the flexible board  202  is different from the flexible board  200  illustrated in  FIGS. 1-3  in that it has plating lead wires  242  in place of the plating lead wires  240 . In other respects, it is substantially the same as the flexible board  200 . 
   Plating lead wires  242 R and  242 L which are connected to terminals  230 R and  230 L, respectively, at the ends of the array of the terminals  230 , may extend along the width of flexible board  202  (extending laterally as shown in  FIG. 5 ). The plating lead wires  242 R and  242 L are an example of “end plating lead wires.” 
   The plating lead wire  242 R may extend from the terminal  230 R along the width to an edge  202   e   2  of the flexible board  202 . The plating lead wire  242 L may extend from the terminal  230 L along the width to a longitudinal edge  202   e   3  of the flexible board  202 . Thus, the plating lead wires  242 R and  242 L do not extend to a lateral edge  202   e 1 at the end of the flexible board  202 . This can help reduce or prevent the occurrence of a short circuit between the terminal  230 R and the adjacent terminal  230  or between the terminal  230 L and the adjacent terminal  230 . 
   With the exception of the plating lead wires  242 R and  242 L, the other plating lead wires  242  may extend from the terminals  230  to the edge  202   e   1  at the end of the flexible board  202 . 
   Referring now to  FIG. 6 , a flexible board  203  will be described in accordance with other embodiments.  FIG. 6  is a plan view of the flexible board  203  in a state substantially similar as that in  FIG. 1 . The connector  300  is omitted from  FIG. 6  because it has a similar configuration as that illustrated in  FIGS. 1-3 . Components of  FIG. 6  that are similar to those shown in  FIGS. 1-3  are identified by the same reference numbers, and descriptions thereof will be omitted as deemed appropriate. 
   With continued reference to  FIG. 6 , the flexible board  203  may be configured such that power-source-side terminals  230   d  of the terminals  230  to which supply potential is applied are dummy terminals. That is, no electric signal is input to or output from the power-source-side terminals  230   d . Thus, even if the flexible board  203  is inserted at an angle into the connector  300  and a short circuit created between the power-source terminals  230   a  and the power-source-side terminals  230   d , potentially little or no ill effect, such as excess current or heat generation, will be exerted on any device connected to the flexible board  203 . 
   Furthermore, in certain embodiments, the power-source-side terminals  230   d  may not be connected to the plating lead wires  240 . This may help reduce or prevent a short circuit between the power-source terminals  230   a  and the power-source-side terminals  230   d  via the plating lead wires  240 . 
   The power-source terminals  230   a  are supplied with supply potential and thus may be higher in potential than the other terminals to which other signals (for example, an image signal and various control signals) are applied. Consequently, if there is a short-circuit between the power-source terminals  230   a  and the other terminals  230 , ill effects such as overcurrent may be exerted on a device connected to the flexible board  203 . Accordingly, the use of the flexible board  203  in accordance with these embodiments can help improve the reliability of a device connected to the flexible board  203  by having the power-source-side terminals  230   d , which are adjacent to the power-source terminals  230   a  to which supply potential is applied, formed as dummy terminals to which the plating lead wires  240  are not connected. 
   Referring now to  FIGS. 7-9 , a liquid crystal device with a flexible board will be described as an example of an electrooptic device in accordance with certain embodiments. In this example, a liquid crystal device  100  with the flexible board  200  of  FIGS. 1-3  will be described. 
   Referring first to  FIGS. 7 and 8 , the overall structure of the liquid crystal device  100  will be described.  FIG. 7  is a plan view of the liquid crystal device.  FIG. 8  is a cross-sectional view taken along line VIII-VIII′ of  FIG. 7 .  FIGS. 7 and 8  depict the liquid crystal device  100  to which the flexible board  200  is not connected. 
   In  FIGS. 7 and 8 , the liquid crystal device  100  includes a TFT array substrate  10  and an opposing substrate  20 . Between the TFT array substrate  10  and the opposing substrate  20  is sealed a liquid crystal layer  50 . The TFT array substrate  10  and the opposing substrate  20  are bonded to each other with a sealing material  52  disposed in the sealing area around an image display area  10   a.    
   Referring to  FIG. 7 , a frame light-shielding film  53  is disposed on the opposing substrate  20 . The frame light-shielding film  53  defines the frame area of the image display area  10   a  inside in parallel to the sealing area in which the sealing material  52  is disposed. In the peripheral area, the area outside the sealing area in which the sealing material  52  is disposed has a data-line driving circuit  101  and external-circuit connection terminals  102  along one side of the TFT array substrate  10 . A sampling circuit  7  is provided inside the sealing area along the one side in such a manner that it is covered with the frame light-shielding film  53 . A scanning-line driving circuit  104  is provided inside the sealing area along two sides adjacent to the one side in such a manner that it is covered with the frame light-shielding film  53 . Vertical conducting terminals  106  for connecting both the substrates with vertical conducting members  107  are disposed at the areas on the TFT array substrate  10  opposing the four corners of the opposing substrate  20 . This allows electrical conduction between the TFT array substrate  10  and the opposing substrate  20 . 
   The TFT array substrate  10  includes routing wires  90  for electrical connection among the external-circuit connection terminals  102 , the data-line driving circuit  101 , the scanning-line driving circuit  104 , and the vertical conducting terminals  106 . 
   Referring now to  FIG. 8 , the TFT array substrate  10  has a layer structure in which thin-film transistors (TFTs) for switching pixels, serving as driving elements, and wires of scanning lines, data lines and so on. The image display area  10   a  has pixel electrodes  9   a  in matrix form on the layer of the pixel-switching TFTs, the scanning lines, and the data lines. The pixel electrodes  9   a  have an alignment layer thereon. The opposing substrate  20  has a light-shielding layer  23  on the surface facing the TFT array substrate  10 . The light-shielding layer  23  is made of, for example, light-shielding metal in a lattice pattern or the like in the image display area  10   a  on the opposing substrate  20 . An opposing electrode  21  made of a transparent material such as indium tin oxide (ITO) is provided over the light-shielding layer  23  so as to be opposed to the pixel electrodes  9   a . The opposing electrode  21  has an alignment layer thereon. The liquid crystal layer  50  is made of one kind nematic liquid crystal or a mixture of several kinds of nematic liquid crystal, and has a predetermined orientation between the pair of alignment layers. 
   Although not shown here, the TFT array substrate  10  may include an inspection circuit or an inspection pattern for inspecting the quality and defect of the liquid crystal device during manufacture or shipment in addition to the data-line driving circuit  101  and the scanning-line driving circuit  104 . 
   Referring next to  FIG. 9 , the connection between the liquid crystal device and the flexible board will be described.  FIG. 9  is a perspective view of the liquid crystal device with a flexible board, in a state in which it is connected to a flexible board.  FIG. 9  shows only components directly related to the connection between the liquid crystal device and the flexible board, and omits other components that may be shown in  FIGS. 1-3 ,  7 , and  8 . 
   With continued reference to  FIG. 9 , the flexible board  200  may be connected to the liquid crystal device  100  in such a manner that connecting portions  225  of the wires  220  opposite to the connector  300  (see  FIG. 1 ) are connected to the external-circuit connection terminals  102 . The connecting portions  225  of the flexible board  200  and the external-circuit connection terminals  102  may be connected together by thermocompression bonding using anisotropic conductive film (ACF). Specifically, ACF may be sandwiched between the connecting portions  225  and the external-circuit connection terminals  102 . A heated head may then be pressed onto the thermocompression area of the connecting portions  225 . Thus, the thermocompression area is heated with pressure such that the connecting portions  225  and the external-circuit connection terminals  102  are bonded together by the ACF and the connecting portions  225  and the external-circuit connection terminals  102  are electrically connected by the conductive particles in the ACF. The ACF may be comprised of conductive particles coated with insulating film and an adhesive. For example, the conductive particles may be fine particles of plastic coated with nickel. The adhesive may be thermoplastic resin or thermosetting resin, of which epoxy thermosetting resin is frequently used in view of reliability. A major characteristic of the ACF when thermocompressed is anisotropy, in which it exhibits conductivity in the vertical direction and an insulating property in the lateral direction. 
   The flexible board  200  may have a control circuit  500 . The control circuit  500  may be connected to the wires  220  and is connected to at least part of the external-circuit connection terminals  102  via the connecting portions  225 . The control circuit  500  may also be connected to the circuits built in the liquid crystal device  100 , such as the data-line driving circuit  101  (see  FIG. 7 ). 
   As described above, the flexible board  200  and the liquid crystal device  100  may be connected together by the thermocompression bonding of the external-circuit connection terminals  102  and the connecting portions  225  to constitute the liquid-crystal device  100  with the flexible board  200  as shown in  FIG. 9 . The use of the liquid crystal device  100  with the flexible board  200  can help reduce the occurrence of a short circuit between adjacent terminals  230  on the flexible board  200  and improve the reliability of the device. 
   Next, an exemplary projector that uses the liquid crystal device or the electrooptic device as a light valve will be described.  FIG. 10  is a plan view of a projector  1100 . 
   As shown in  FIG. 10 , the projector  1100  accommodates a lamp unit  1102  including a white light source such as a halogen lamp. The light emitted from the lamp unit  1102  is separated into the three primary colors of RGB by four mirrors  1106  and two dichroic mirrors  1108  disposed in a light guide  1104 , and enters liquid crystal panels  1110 R,  1110 G, and  1110 B serving as light valves corresponding to the respective primary colors. 
   The liquid crystal panels  1110 R,  1110 G, and  1110 B have a similar structure as the above-described liquid crystal device, which are driven by primary-color signals of RGB applied from an image-signal processing circuit, respectively. The light modulated by the liquid crystal panels  1110 R,  1110 G, and  1110 B enter the dichroic prism  1112  from three directions. The dichroic prism  1112  refracts R and B light at 90° and allows G light to go straight. The images of the colors are combined, and thus a color image is projected onto, for example, a screen, through a projection lens  1114 . 
   Next, the display images by the liquid crystal panels  1110 R,  1110 G, and  1110 B will be described. The display image by the liquid crystal panel  1110 G will need to be reversed left to right with respect to the display images by the liquid crystal panels  1110 R and  1110 B. 
   The liquid crystal panels  1110 R,  1110 G, and  1110 B do not need a color filter because corresponding RGB light enter the liquid crystal panels  1110 R,  1110 G, and  1110 B through the dichroic mirrors  1108 . 
   In addition to the exemplary electronic device described with reference to  FIG. 10 , electronic devices may include portable personal computers, portable phones, liquid-crystal televisions, viewfinder or monitor-direct-view type videotape recorders, car navigation systems, pagers, electronic notebooks, calculators, word processors, workstations, TV phones, POS terminals, and devices having a touch panel. 
   Other embodiments include a reflective liquid crystal device that has elements on silicon (LCOS), a plasma display (PDP), a field-emission display (FED), a surface-conduction electron-emitter display (SED), an organic EL display, a digital micromirror device (DMD), and an electrophoresis device. 
   It should be understood that the preceding is merely a description of several embodiments. While specific embodiments and applications have been illustrated and described, it is to be understood that the precise configuration and components disclosed herein is illustrative only and not limiting in any sense. Having the benefit of this disclosure, various modifications, changes, and variations will be apparent to those of ordinary skill in the art without departing from the spirit and scope of the principles disclosed. Thus, to the maximum extent allowed by law, the scope of the invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing description.