Patent Publication Number: US-7722245-B2

Title: Display device

Description:
BACKGROUND 
   1. Field of Invention 
   The present invention relates to a display device. More particularly, the invention relates to a display device that is basically tubular and has a display panel disposed along the outside circumference. 
   2. Description of Related Art 
   Tubular display devices that are worn on the wrist, for example, are known from the literature. The frame of the display device may have a thin display panel such as an electrophoretic display panel disposed along the outside circumference surface of the frame as taught in Japanese Unexamined Patent Appl. Pub. JP-A-2005-250442. 
   The display panel (display unit) of the display device taught in JP-A-2005-250442 is connected to a flexible printed circuit that is populated with the electronic components for driving the display device by a connector unit. The display panel and flexible printed circuit are folded together at the connector unit. The flexible printed circuit is disposed directly on the outside surface of the bobbin-shaped frame, and the display panel is disposed above the outside of the flexible printed circuit with a gap therebetween so that the flexible printed circuit is between the display panel and the frame. 
   If the electrophoretic display panel or other thin display panel is distorted, however, the distortion can degrade the image quality. It is therefore necessary in a display device that has a thin display panel disposed around the outside surface to install the display panel in a stable manner without applying unnecessary force. 
   In the display device taught in JP-A-2005-250442 the display panel must be rendered so that it is stable and substantially annular even though the display panel is floating above the flexible printed circuit. This can be done, for example, by holding the opposite edges of the display panel between a pair of rails disposed around the entire circumference of the frame. Because the restoring force of the display panel bent into a ring is suppressed by the rails disposed around the circumference of the frame, the display panel is easily distorted and image quality may be degraded. 
   SUMMARY 
   The display device of the invention reduces the fixed parts of the display panel and stably disposes the display panel substantially in a ring. 
   A display device according to a preferred aspect of the invention has a frame having a substantially cylindrically shaped cylindrical part, a display panel that is band shaped and flexible, and a spacer that is substantially cylindrically shaped and is fit to the cylindrical part. The display panel is disposed to the outside surface of the spacer. 
   Examples of such a display device are a wristwatch and a cell phone, and examples of a band-shaped display panel are an electrophoretic display panel and an organic electroluminescent (EL) panel. 
   The display panel in this aspect of the invention is disposed around the outside surface of the substantially cylindrical spacer. Because the bottom of the display panel is in contact with the spacer, the display panel can be disposed in a stable condition and can be disposed in a substantially annular shape. 
   Furthermore, because the bottom of the display panel is in contact with the spacer, the display panel can be disposed in a stable condition by simply securing both end parts of the display panel with double-sided tape, for example. The display panel can also be disposed with only a small portion of the display panel affixed. The force applied by securing the display panel can also be reduced and distortion can be reduced. The drive circuit unit for driving the display panel (corresponding to the flexible printed circuit in JP-A-2005-250442) can be held between the spacer and the cylindrical part, for example. 
   The spacer in the display device of the invention preferably has a non-contiguous break in one part in the circumferential direction and is elastically deformable. 
   If the spacer must be forcibly fit to the cylindrical part because the spacer and the cylindrical part of the frame fit too tightly due to variations in manufacture, the spacer can become distorted, thus also distorting the display panel and possibly degrading the image quality. The spacer could also be cracked if the spacer is fit with excessive force. 
   By forming a break at one part in the circumferential direction of the spacer and making the spacer elastically deformable, the invention enables spreading the gap at the break. This enables easily fitting the spacer to the cylindrical part if manufacturing variations cause the spacer to fit too tightly to the cylindrical part. Distortion of the spacer and therefore the display panel due to forcibly fitting the spacer to the cylindrical part can thus be reduced. Cracking of the spacer can also be prevented. 
   Furthermore, because a break is formed at one part in the circumferential direction of the spacer and the spacer is elastically deformable, the spacer can absorb the force of impact and vibrations that are applied when the display device is dropped, for example, and the effect of impact and vibration on the display device can be reduced. 
   Further preferably, the display device also has a holding part that is disposed to the outside surface of the spacer and has a pair of channels for slidably holding each lengthwise end part of the display panel. The display panel is held with substantially the middle part between the lengthwise ends adhesively attached to the spacer and both lengthwise ends held in the holding part. 
   Methods of adhesively attaching the middle part of the display panel to the spacer include using double-sided tape and using an adhesive. 
   If the holding parts having a pair of channels are formed around the entire circumference of the spacer, the display panel will be constrained around the entire circumference as it tries to return to its original shape after being deformed into a circle. The display panel is easily distorted in this case, and the image quality may be degraded. 
   The holding parts of the invention secure the display panel at both end parts and in the middle, and leave the portions between the end parts and the middle free. As a result, if compressive force is applied to the portion between the end parts and the middle, this portion can bend and distortion can therefore be suppressed. 
   In addition, if only both end parts of the display panel are secured, the restoring force of the display panel tends to cause particularly the middle part of the display panel to separate from the spacer. The invention secures both the end parts and the middle, however, can therefore dispose the display panel sufficiently tightly to the spacer, and thus holds the display panel in a more stable condition. 
   Furthermore, because the middle part is adhesively affixed to the spacer, the force pressing on the display panel can be reduced and distortion can be more effectively suppressed compared with securing the middle part of the display panel to the spacer by means of a holding part having channels. 
   Further preferably, the display device has a panel abutment part that is abutted by one lengthwise end of the display panel disposed to the outside surface of the spacer, and a gap that connects the inside with the outside of the spacer and enables inserting the other lengthwise end of the display panel. 
   When a break is rendered at one part in the circumferential direction of the spacer, this gap that connects the inside with the outside of the spacer and enables inserting the other lengthwise end of the display panel can be a gap rendered between the circumferential ends of the space or the gap can be a slit formed in the spacer. 
   Because this aspect of the invention has a panel abutment part, the display panel can be easily positioned to the spacer and therefore to the frame by simply setting one end of the display panel against the abutment. 
   Furthermore, because a gap enabling inserting the display panel is rendered in the spacer, if variations in manufacture result in the display panel being slightly too long, the excess length portion can be inserted to this gap and disposed in this gap and between the spacer and the cylindrical part. The display panel can therefore be disposed more tightly to the spacer. 
   Yet further preferably, the display device has a protruding part that is disposed projecting to the outside on the outside surface of the cylindrical part of the frame, and a groove that can hold the protruding part and is disposed to the inside circumference surface of the spacer at a position corresponding to the protruding part. 
   Because a groove that can hold the protruding part is disposed to the inside circumference surface of the spacer at a position corresponding to the protruding part in this aspect of the invention, the spacer and therefore the display panel can be easily positioned to the frame by simply fitting the protruding part into the groove. 
   Furthermore, because the groove is disposed to the inside surface of the spacer, the spacer can be opened more easily when a break is provided in the spacer, and the spacer can therefore be even more easily fit to the cylindrical part. 
   In a display device according to another aspect of the invention the frame has a body and a cover part, the body includes the cylindrical part and a flange part that projects to the outside from one axial end side of the cylindrical part, a plurality of the protruding parts are disposed to the other axial end side of the cylindrical part and a screw hole is formed in each of the protruding parts, and the cover part is flat, has holes formed at positions corresponding to each of the screw holes, and is secured by screws on the other end side of the cylindrical part where the protruding parts are formed so that the cover part opposes the flange part. 
   These screw holes can be screw holes that do not pass through the protruding parts, or screw holes (holes) that pass through. 
   In this aspect of the invention the protruding parts function both for positioning the spacer and for securing the cover part, and thus afford a simpler arrangement. 
   The display device according to another aspect of the invention also has a battery that is the drive power source for the display panel. The display panel is disposed around substantially the entire circumference on the outside surface of the spacer, both end parts of the display panel in the circumferential direction are disposed separated by a prescribed distance, and the battery is disposed between the end parts of the display panel. 
   The battery is a button battery or other primary battery, or a rechargeable secondary battery. The gap between the ends of the display panel is at least large enough to hold the battery, but the gap is preferably as small as possible in order to maximize the display area of the display panel. 
   This aspect of the invention disposes the battery between the circumferential ends of the display panel wrapped around the outside circumference surface of the frame, and the display panel and the battery therefore do not overlap. The thickness in the part where the display panel and the battery are located can therefore be reduced compared with an arrangement in which the display panel and the battery overlap, and a thinner design can therefore be achieved. 
   Yet further preferably, the display device has a cover member that covers at least the battery. 
   The area covered by the cover member at least includes the entire battery. The cover member may also cover the gaps between the ends of the display panel and the battery. The cover member may also cover both ends of the display panel. 
   Because the cover member in this aspect of the invention covers at least the battery, the battery that is desirably not exposed for aesthetic reasons can be hidden, decorativeness can be improved, and a pleasing appearance can be achieved. 
   The shape of the cover member preferably conforms to the outside surface of the frame. If an inflexible battery such as a button battery is located in the surface of the frame, the battery cannot be curved to follow the surface shape of the frame. However, by covering the battery with a cover member that conforms to the shape of the frame, a uniform appearance can be achieved over the entire surface of the frame. 
   Yet further preferably, the display device also has a cover member position indication part for positioning the cover member disposed to the display panel, and the cover member position indication part can be displayed when positioning the cover member. 
   Because this arrangement has a cover member position indication part disposed to the display panel, the cover member position indication part can be illuminated during assembly for aligning the ends of the cover member with the cover member position indication part. The cover member can therefore be easily positioned. Assembly is therefore more efficient. 
   After positioning the cover member is completed the cover member position indication part can be turned off so that the cover member position indication part is not exposed and a good appearance can be achieved. 
   Yet further preferably, the display device also has a protruding part that is disposed to the spacer and enables positioning the cover member by contacting the cover member. 
   Because this aspect of the invention has a protruding part that is disposed to the spacer and enables positioning the cover member by contacting the cover member, the cover member can be easily positioned in a short time during assembly and assembly is therefore more efficient. 
   In the display device according to another aspect of the invention the cover member has a photoelectric conversion means for converting light energy to electrical energy, and the battery is a secondary cell that stores the electrical energy output by the photoelectric conversion means. 
   Because the cover member is a photoelectric conversion means and the battery is a secondary battery in this aspect of the invention, electrical energy can be constantly supplied even if the electrical energy stored in the secondary battery is supplied to other parts because the electrical energy newly produced by the photoelectric conversion means can be stored in the secondary battery. Compared with an arrangement that uses a primary battery, this arrangement eliminates the need to regularly replace the battery and thereby reduces the burden on the user. There are also no depleted waste batteries to throw away, and the display device is therefore environmentally friendly. 
   In the display device according to another aspect of the invention the frame has a body and a cover part, the body includes the cylindrical part and a flange part that projects to the outside from one axial end side of the cylindrical part, the cover part is flat, has an opening that is the same size and the same shape as the shape of the end part of the cylindrical part, has an outside circumference shape that is the same size and the same shape as the outside circumference shape of the flange part, and can be removably attached to the other end of the cylindrical part opposite the flange part, a cylindrical transparent member is disposed to the outside surface of the display panel, the transparent member is held between the flange part and the cover part, and the battery is located between the cylindrical part and the transparent member and is disposed so that the battery can be moved toward the cover part and replaced by removing the cover part. 
   In this aspect of the invention the battery is located between the cylindrical part of the body and the transparent member and is disposed so that the battery can be moved toward the cover part and replaced by removing the cover part. The battery can therefore be easily replaced. Furthermore, because removing the transparent member is not necessary to replace the battery, dust, lint, and other foreign matter can be prevented from getting inside the frame. 
   The display device according to another aspect of the invention also has a cover member that covers at least the battery, the frame has a body and a cover part, the body includes the cylindrical part and a flange part that projects to the outside from one axial end side of the cylindrical part, the cover part is flat, has an opening that is the same size and the same shape as the shape of the end part of the cylindrical part, has an outside circumference shape that is the same size and the same shape as the outside circumference shape of the flange part, and can be removably attached to the other end of the cylindrical part opposite the flange part, a cylindrical transparent member is disposed to the outside surface of the display panel, the spacer and the transparent member are held between the flange part and the cover part, and the cover member is covered by the transparent member. 
   By covering the display panel and the cover member with the transparent member, the display panel and the cover member in this aspect of the invention are reliably secured and protected from scratching and soiling. 
   Furthermore, because the spacer, the display panel, and the transparent member that are disposed on the outside of the cylindrical part of the body are held between the flange part and the cover part of the body, the spacer, the display panel, and the transparent member can be reliably secured to the frame and can be easily assembled. 
   The display device of the invention can reduce the fixed parts of the display panel and can stably dispose the display panel substantially in a ring. 
   Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an oblique view showing a timepiece as a display device according to a first embodiment of the invention. 
       FIG. 2  is an exploded oblique view of the timepiece in this embodiment of the invention. 
       FIG. 3  is a plan view of a display module in this embodiment of the invention. 
       FIG. 4  is a section view of the display module in this embodiment of the invention. 
       FIG. 5  is a schematic view showing the display panel in this embodiment of the invention. 
       FIG. 6  is an enlarged view of the holding parts of the spacer in this embodiment of the invention. 
       FIG. 7  is a side section view of the timepiece from the flange side part in this embodiment of the invention. 
       FIG. 8  is a section view through line D-D in  FIG. 7 . 
       FIG. 9  is a section view through line A-A in  FIG. 7 . 
       FIG. 10  is a section view through line B-B in  FIG. 7 . 
       FIG. 11  is a section view through line C-C in  FIG. 7 . 
       FIG. 12  is a section view showing a part of the timepiece in this embodiment of the invention. 
       FIG. 13  shows the electrical arrangement of the timepiece in this embodiment of the invention. 
       FIG. 14  is an oblique view of the cover member of the timepiece in this embodiment of the invention. 
       FIG. 15  is a partial plan view showing the position where the cover member is disposed in the timepiece according to this embodiment of the invention. 
       FIG. 16  shows the electrical arrangement of the timepiece in a second embodiment of the invention. 
       FIG. 17  is a section view showing a part of the timepiece in this embodiment of the invention. 
       FIG. 18  is an oblique view of the spacer in a timepiece according to a variation of the invention. 
       FIG. 19  is a partial plan view showing the position where the cover member is disposed in the timepiece according to a variation of the invention. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Preferred embodiments of the present invention are described below with reference to the accompanying figures. 
   Note that in the second and subsequent embodiments described below parts that are the same as or functionally similar to equivalent parts in the first embodiment are identified by the same reference numerals and further description thereof is simplified or omitted. 
   Embodiment 1 
   1. General Configuration 
     FIG. 1  is an oblique view of a timepiece  1  according to a first embodiment of the invention. The timepiece  1  described below as a display device according to the present invention is a bracelet type timepiece that is formed in a ring as shown in  FIG. 1  and is worn on the wrist. An electrophoretic display panel  5  for displaying the time and date is disposed around the entire circumference on the outside of the timepiece  1 . 
     FIG. 2  is an exploded oblique view of the timepiece  1 . 
   As shown in  FIG. 2  the timepiece  1  includes a substantially annular frame  3 , a substantially annular spacer  4  that fits onto the frame  3 , a display module  2  disposed to the spacer  4 , and a glass crystal  6  as an annular transparent member. The spacer  4  has the display panel  5  and a switching circuit board  94 . The display panel  5  is covered by the glass crystal  6 . The axis A in  FIG. 2  is the virtual center axis of the frame  3 , the spacer  4 , the display module  2 , and the glass crystal  6 . 
   As shown in  FIG. 2  the frame  3  includes a body  31  and a back cover  32  as a cover member. 
   The body  31  includes a cylindrical part  311  as a body tube, and a flange  312  that protrudes radially from one end edge of the cylindrical part  311  so that the body  31  is L-shaped when seen in section. 
   A plurality of protrusions  313  project radially to the outside from the other end edge of the cylindrical part  311 . A screw hole  314  is formed in each of the protrusions  313 . 
   The back cover  32  is formed from a flat member with an inside circumference shape (an opening) that is the same size and shape as the inside circumference shape of the cylindrical part  311 , and an outside circumference shape that is the same size and shape as the outside circumference shape of the flange  312 . Holes  321  are formed at positions corresponding to the screw holes  314  in the protrusions  313 . The back cover  32  is fastened to the cylindrical part  311  by a plurality of screws  33  that are screwed through the holes  321  into the screw holes  314 . 
   As described in further detail below, after the display module  2  is assembled to the spacer  4 , the spacer  4  is fit to the frame  3  and is held between the back cover  32  and the flange  312 . 
   The glass crystal  6  is held between the back cover  32  and the flange  312  and covers the display panel  5 . 
   2. Arrangement of the Display Module and the Drive Circuit Unit 
     FIG. 3  is a plan view of the display module  2 , and  FIG. 4  is an end section view of the display module  2 . Note that the drive circuit unit  7  and the switch circuit  94  are drawn shorter in  FIG. 3  and  FIG. 4  than in  FIG. 2 . 
   As shown in  FIG. 3  the display module  2  includes the drive circuit unit  7 , the switch circuit  94  that sends input signals to the drive circuit unit  7 , and the display panel  5  that is driven and controlled by the drive circuit unit  7  to display the time, for example. A tactile switch  93  is disposed to the switch circuit  94  so that the tactile switch  93  is depressed when the operator presses an operating button  91  (see  FIG. 11 ) and the switch circuit  94  sends an input signal to the drive circuit unit  7 . The drive circuit unit  7 , the switch circuit  94 , and the display panel  5  are manufactured separately. The drive circuit unit  7  and the display panel  5  are connected by a wiring member C 1  such as an anistropic conductive film (ACF), and the drive circuit unit  7  and the switch circuit  94  are connected by an identical wiring member C 2 . The drive circuit unit  7  and the switch circuit  94  are flexible printed circuits that are made from polyimide, polyester, or other flexible plastic material. 
   As shown in  FIG. 3  and  FIG. 4 , the display module  2  is folded over at the wiring member C 1  connecting the display panel  5  to the drive circuit unit  7 . As indicated by the double-dot dash line in  FIG. 4 , the drive circuit unit  7  is folded over to the back of the display panel  5 . As shown in  FIG. 3 , the drive circuit unit  7  has a controller  71  for controlling the timepiece  1 , a driver IC  72  as the drive device of the display panel  5 , and a crystal oscillation circuit element  73 . 
   3. Arrangement of the Electrophoretic Display Panel 
   As shown in  FIG. 4  the display panel  5  includes a display circuit  51 , a transparent circuit  52 , and an electrophoretic layer  53  disposed between the display circuit  51  and the transparent circuit  52 . The display circuit  51  and the transparent circuit  52  are also flexible printed circuits made from polyimide, polyester, or other flexible plastic material. As shown in  FIG. 4  this display panel  5  is curved substantially 360° substantially into a circle so that the opposite ends are separated a prescribed distance from each other. 
   As shown in  FIG. 4 , the display circuit  51  is thinner than the transparent circuit  52 . A plurality of microcapsules  531  are bonded to the top part of the display circuit  51 . 
   Moisture resistant sheets  54 A and  54 B are disposed to the top and the bottom sides of the transparent circuit  52 . These moisture resistant sheets  54 A and  54 B seal the display panel  5  and prevent water from penetrating to the electrophoretic layer  53 . 
   More specifically, the inside surfaces of the moisture resistant sheets  54 A and  54 B are coated with a hot melt adhesive layer, the ends of the moisture resistant sheets  54 A and  54 B are bonded using a vacuum laminator, for example, and the moisture resistant sheets  54 A and  54 B are bonded to the transparent circuit  52  and the display circuit  51 , thereby sealing the transparent circuit  52 , the electrophoretic layer  53 , and the display circuit  51  at the ends and top and bottom surfaces of the circuits. 
     FIG. 5  is a schematic section view showing the arrangement of the display panel  5 . 
   As shown in  FIG. 5  segment electrodes  510  of the same shape as the segments  55  (see  FIG. 3 ) are disposed on the top surface of the display circuit  51  at positions corresponding to each of the segments  55 . 
   A transparent common electrode  520  made of indium tin oxide (ITO), for example, is disposed over substantially the entire back surface of the transparent circuit  52  (the side facing the display circuit  51 ). The common electrode  520  is an electrode that is common to each of the segment electrodes  510 . 
   The electrophoretic layer  53  is rendered by a dense distribution of numerous microcapsules  531  as shown in  FIG. 5 . Each of the microcapsules  531  is filled with an electrophoretic particle suspension  532  in which numerous charged particles are dispersed. Black electrophoretic particles  532 B (“black particles” below) and white electrophoretic particles  532 W (“white particles” below) that are charged to the opposite polarity as the black particles are dispersed in the electrophoretic particle suspension  532 . In this embodiment of the invention the black particles  532 B are positively charged and the white particles  532 W are negatively charged. 
   When the particles are charged as described above and the common electrode  520  is driven to a high level potential (H potential), a field flowing from the common electrode  520  to the segment electrodes  510  is produced by the potential difference in the segments  55  for which the segment electrodes  510  is driven to a low level potential (L potential). This causes the positively charged black particles  532 B to migrate to the segment electrodes  510  and the negatively charged white particles  532 W to migrate to the common electrode  520  so that the segment  55  is white. 
   No field is produced in the segments  55  where the potential of the segment electrodes  510  is equal to the potential of the common electrode  520 , and the display color therefore does not change. 
   When the common electrode  520  then goes to a low level (L potential), a field flowing in the opposite direction is produced in the segments  55  for which the segment electrodes  510  are a high level (H potential). This causes the negatively charged white particles  532 W to migrate to the segment electrodes  510  and the positively black particles  532 B to migrate to the common electrode  520  so that the segment  55  is black. 
   As noted above, no field is produced in the segments  55  where the potential of the segment electrodes  510  is equal to the potential of the common electrode  520 , and the display color therefore remains the same. 
   Migration of the black particles  532 B and the white particles  532 W can be adjusted by adjusting the time the voltage is applied and the applied voltage so that intermediate colors between black and white can be displayed. 
   Images can thus be formed on the display panel  5  by changing the color displayed in each of the segments  55 . 
   4. Arrangement of the Spacer 
   The spacer  4  is for disposing the display panel  5  in a stable, substantially annular state. The spacer  4  is plastic. As shown in  FIG. 2 , the spacer  4  includes a spacer body  41  that is non-contiguous in part circumferentially and is flexibly deformable, and a holder retaining part  42  rendered in unison with the spacer body  41  on one end in the circumferential direction of the spacer body  41 . 
   5. Arrangement of the Spacer Body 
     FIG. 6  is an enlarged view of the holding parts  411 A,  411 B of the spacer  4 . 
   As shown in  FIG. 6 , a first holding part  411 A is disposed to both sides of one end of the spacer body  41  in which the holder retaining part  42  is disposed. A pair of channels  412  for slidably holding the distal end of the display panel  5  is formed in the first holding part  411 A. 
   Note that herein the proximal end of the display panel  5  means the end that is connected to the drive circuit unit  7 , and the distal end means the end that is not connected to the drive circuit unit  7 . 
   A panel abutment  413  that joins the distal ends of the first holding part  411 A rises across the width of the one end of the spacer body  41 . This panel abutment  413  contacts the distal end of the display panel  5  when the display panel  5  is inserted and thus positions the display panel  5 . 
   A second holding part  411 B having a pair of channels  412  for slidably holding the proximal end of the display panel  5  is disposed at the other end of the spacer body  41 . 
   As shown in  FIG. 2 , guide parts  414  for guiding the display panel  5  are disposed opposite the holding parts  411 A,  411 B on the outside circumference of the spacer body  41 . Ribs  415  that reinforce the spacer body  41  are disposed around substantially the entire circumference of the spacer body  41 . The ribs  415  form a storage space X (see  FIG. 8 ) between the spacer body  41  and the cylindrical part  311 . The drive circuit unit  7  and the button input unit  9  including the switch circuit  94  as described below are disposed in the storage space X. 
   As shown in  FIG. 6 , a battery holder  81  is stored in the holder retaining part  42  so that the battery holder  81  can slide parallel to the width of the spacer  4 . A primary battery  10  described below is stored in this battery holder  81 . The battery holder  81  and the primary battery  10  render the battery storage unit  8  described below. 
   A gap S sized to enable inserting the display module  2  is formed between the holder retaining part  42  and the other end of the spacer body  41  where the second holding part  411 B is formed as shown in  FIG. 6 . The spacer  4  is thus non-contiguous at one part in the circumferential direction and a long, narrow gap S enabling inserting the display module  2  is formed at this break in the spacer  4 . 
   As described above, the distal end of the display panel  5  is held by the first holding part  411 A and the proximal end of the display panel  5  is held by the second holding part  411 B. The middle part of the display panel  5  is adhesively affixed to the spacer body  41  by double-sided tape T 1  (see  FIG. 7 ) applied to the spacer body  41 . The display panel  5  can therefore be disposed in a ring along the outside surface of the basically tubular spacer body  41 . The display panel  5  can also be disposed in a stable condition by pressing substantially the entire bottom surface of the display panel  5  at the double-sided tape T 1  to the spacer body  41 . 
   Furthermore, because only both edge parts and the middle part of the display panel  5  are fixed, the force applied to the display panel  5  when the display panel  5  is affixed can be reduced and distortion can be prevented. 
   Furthermore, because the middle part is adhesively secured with double-sided tape T 1 , the force pressing on the display panel  5  can be reduced in comparison with securing the middle part by means of the channels  412  in the holding parts  411 A,  411 B, and distortion can be further reduced. 
   The part of the display module  2  below the part that is held by the second holding part  411 B is folded back at the part in the gap S in the spacer  4  and is stored in the storage space X in the bottom of the spacer body  41 . By thus rendering this gap S in the spacer  4 , any portion of the display panel  5  that is slightly longer than the outside surface of the spacer body  41  due to manufacturing variations can be disposed in this gap S formed in the spacer  4  and the storage space X in the bottom of the spacer body  41 , and the display panel  5  can therefore be disposed more tightly to the spacer body  41 . 
     FIG. 7  is a side section view of the timepiece  1  as seen from the flange  312  side, and  FIG. 8  is a section view through line D-D in  FIG. 7 . 
   As shown in  FIG. 8 , the drive circuit unit  7  is affixed to the inside circumference surface of the spacer body  41  by double-sided tape T 2 . As also shown in  FIG. 8 , a dielectric seal Z for protecting the drive circuit unit  7 , for example, is attached to the cylindrical part  311  of the frame  3 . 
     FIG. 9  is a section view through line A-A in  FIG. 7 . 
   As shown in  FIG. 2 , the spacer body  41  includes a flange-side member  41 A and a back-cover-side member  41 B. A plurality of connection pins  416  are formed on the inside of the flange-side member  41 A projecting towards the back-cover-side member  41 B as shown in  FIG. 9 . A hole  417  is formed at a position corresponding to each of the connection pins  416  on the inside of the back-cover-side member  41 B. The spacer body  41  is assembled by fitting these connection pins  416  into the matching holes  417  to connect the flange-side member  41 A and the back-cover-side member  41 B. 
     FIG. 10  is a section view through line B-B in  FIG. 7 . 
   Channels  418  for holding the protrusions  313  are disposed to the inside circumference surface of the back-cover-side member  41 B at positions corresponding to the protrusions  313  formed on the body  31  of the frame  3 . The channels  418  are formed in line with the axis of the spacer  4 . 
   After the spacer  4  is spread and fit onto the cylindrical part  311  of the frame  3 , the spacer  4  is positioned by fitting the protrusions  313  into the channels  418  as shown in  FIG. 10 . The channels  418  also function to make spreading the spacer  4  open easier, and these channels  418  therefore make fitting the spacer  4  to the cylindrical part  311  easier. 
   6. Arrangement of the Button Input Unit 
     FIG. 11  is a section view through line C-C in  FIG. 7 . 
   As shown in  FIG. 7 , three button input units  9  for controlling the timepiece  1  are disposed to the timepiece  1  according to this embodiment of the invention. As shown in  FIG. 11 , each button input unit  9  includes an operating button  91 , an arm part  92 , a tactile switch  93 , a support wall  419 , and a switch circuit  94 . 
   The operating button  91  is disposed protruding to the outside from the side of the flange  312  and is supported so that it can be pushed into and out of the frame  3 . The end part of the operating button  91  on the inside part of the frame  3  contacts the arm part  92 . The arm part  92  is disposed slidably inside the frame  3  at a position matching the in-out sliding action of the operating button  91 . 
   The arm part  92  has a coil spring  95 , and this coil spring  95  urges the operating button  91  in the direction causing the operating button  91  to protrude from the frame  3 . The operating button  91  is thus normally held in the protruding position. 
   The tactile switch  93 , which is soldered to the switch circuit  94 , is disposed at the opposite end of the arm part  92  as the operating button  91 . The end part of the tactile switch  93  on the opposite side as the side facing the arm part  92  is supported by the support wall  419  rising from the spacer  4 . 
   The switch circuit  94  is affixed by double-sided tape T 3  to the inside circumference surface of the spacer  4 . 
   The distal end of the arm part  92  does not touch the tactile switch  93  when the operating button  91  is in the protruding position. When the operating button  91  is depressed, the distal end of the arm part  92  moves toward the tactile switch  93  and presses the tactile switch  93 . By rendering the support wall  419  to the spacer  4  in this embodiment of the invention, the tactile switch  93  can be supported by the support wall  419  so that the load on the soldered part of the tactile switch  93  can be reduced. The tactile switch  93  will therefore not separate from the switch circuit  94  and fall even if the tactile switch  93  is repeatedly pressed by the arm part  92 . 
   As described above, the switch circuit  94  is connected to the drive circuit unit  7  by a wiring member C 2 . When the tactile switch  93  is pressed, an input signal from the switch circuit  94  is sent to the drive circuit unit  7  and the display panel  5  is controlled. 
   7. Arrangement of the Battery Storage Unit 
   The battery storage unit  8  holds a primary battery  10  so that the primary battery  10  can be replaced. As described above the battery storage unit  8  includes the battery holder  81  and the primary battery  10  (a button battery) that is held in the battery holder  81 . 
     FIG. 12  is a side section view of the battery storage unit  8  of the timepiece  1 . As shown in  FIG. 12  the primary battery  10 , which is a battery for supplying power to the other parts of the timepiece  1 , is located between the cylindrical part  311  of the body  31  and the glass crystal  6 . The primary battery  10  is disposed in an area B between the ends of the display module  2 . More specifically, the primary battery  10  is located between both end parts of the electrophoretic display panel  5  in the circumferential direction of the cylindrical part  311  of the body  31 . 
   The battery storage unit  8  includes a positive-side presser member  82  and a negative-side presser member  83 . The positive-side presser member  82  is metal and substantially C-shaped in section, covers the outside circumference side of the battery holder  81 , and presses against the positive terminal of the primary battery  10 . The negative-side presser member  83  is metal, is disposed between the primary battery  10  and the cylindrical part  311 , and presses against the negative terminal of the primary battery  10 . 
   The battery storage unit  8  thus comprised is housed in the holder retaining part  42  so that the battery storage unit  8  can slide parallel to the width of the spacer  4 . The positive and negative presser members  82  and  83  are connected by conductors to the drive circuit unit  7  of the display module  2  to supply power to other parts. 
     FIG. 13  shows the electrical arrangement of the timepiece  1 . The controller  71  that is mounted on the drive circuit unit  7  is electrically connected to the display panel  5 , the primary battery  10 , to the button input units  9  having the operating buttons, and to the oscillation unit  11 . The oscillation unit  11  generates the oscillation pulses that are counted by the timekeeping unit not shown to keep the time. 
   8. Decorative Plate Arrangement 
   A decorative plate  50  (see  FIG. 9  and  FIG. 10 ) is disposed on the outside side of the battery storage unit  8  as shown in FIG.  7  as a cover member for covering the battery storage unit  8  and the gap S in the spacer  4 . Decoration is imparted to the surface of the decorative plate  50 . More specifically, the decorative plate  50  has a pattern not shown that is rendered by a complex and advanced processing method to impart a feeling of high quality. The decorative plate  50  also covers the battery storage unit  8  and the gap S in the spacer  4  in this embodiment of the invention to afford a nice appearance. 
     FIG. 14  is an oblique view of the decorative plate  50 .  FIG. 15  is a partial plan view showing the position where the decorative plate  50  is disposed. The decorative plate  50  is formed with a curve conforming to the outside shape of the body  31  of the frame  3 . Both ends of the decorative plate  50  in the circumferential direction of the frame  3  are curved when seen in plan view as shown in  FIG. 15 . 
   Decorative plate position indication units  511  (“position indication units” below) are formed as cover member position indication parts at both circumferential ends of the display panel  5  for positioning the decorative plate  50 . The position indication units  511  are provided to illuminate and show where the decorative plate  50  is positioned. The position indication units  511  are formed in a line in one place at each end of the display panel  5 . The distance between the position indication units  511  along the outside surface of the frame  3  is the same as the length of the decorative plate  50  along the outside surface of the frame  3 . The ends of the decorative plate  50  can thus be positioned according to the position indication units  511  disposed to the display panel  5 . 
   9. Timepiece Assembly 
   Assembling the timepiece  1  is described next. 
   The display module  2  is first attached to the spacer  4 . More specifically, the distal end of the display panel  5  is passed through the channels  412  of the second holding part  411 B of the spacer  4 , then inserted to the channels  412  of the first holding part  411 A until the distal end of the display panel  5  contacts the panel abutment  413  to position the display panel  5  to the spacer  4 . The middle part of the display panel  5  is then pressed to the double-sided tape T 1  that was previously fixed to the middle part of the spacer body  41  to bond the middle of the display panel  5  to the spacer body  41 . 
   The wiring member C 1  and the excess length part of the display panel  5 , if the length of the display panel  5  is somewhat longer than the length along the outside circumference of the spacer body  41  due to manufacturing variations, are then passed through the gap S in the spacer  4 , then folded over at this gap S, and the drive circuit unit  7  is affixed to the inside circumference surface of the spacer  4  by the double-sided tape T 2 . The switch circuit  94  is then affixed to the inside circumference surface of the spacer  4  by the double-sided tape T 3 . This attaches the display module  2  to the spacer  4 . 
   The battery storage unit  8  holding the primary battery  10  is then installed to the holder retaining part  42  of the spacer  4 . 
   After assembling the display module  2  and the battery storage unit  8  to the spacer  4 , the spacer  4  is spread open and fit onto the cylindrical part  311  of the frame  3 , the protrusions  313  of the cylindrical part  311  are fit into the channels  418  disposed to the inside circumference of the spacer  4 , and the spacer  4  is thus positioned to the frame  3 . 
   The decorative plate  50  for hiding the battery storage unit  8  and the gap S in the spacer  4  is then positioned to the outside of the battery storage unit  8 , and the glass crystal  6  is fit outside the display module  2  and the decorative plate  50 . The back cover  32  is then fastened with screws to the body  31  and assembly is completed. 
   10. Positioning the Decorative Plate 
   Positioning the decorative plate  50  during assembly is described next. 
   The position indication units  511  of the display panel  5  shown in  FIG. 15  are first turned on to illuminate. The display panel  5  is then positioned so that the ends of the decorative plate  50  are aligned with the position indication units  511 . The position indication units  511  are then turned off. The position indication units  511  can be turned on only for positioning the decorative plate  50  and can be kept off during normal use. 
   This enables easily and accurately positioning the decorative plate  50 . 
   11. Replacing the Primary Battery 
   Replacing the primary battery  10  is described next. 
   The first step is to unscrew the screws  33  shown in  FIG. 1  and remove the back cover  32  from the body  31 . The battery holder  81  shown in  FIG. 6  and  FIG. 12  is then slid along axis A to remove the battery holder  81  from the spacer  4 . The primary battery  10  held in the battery holder  81  is then replaced. The battery holder  81  is then installed to the spacer  4  and the back cover  32  is fastened with screws to the body  31  by reversing the procedure described above. 
   The primary battery  10  is thus replaced. 
   12. Effect of this Embodiment of the Invention 
   The effect of this embodiment of the invention is described next. 
   (1) The display panel  5  can be disposed in a stable, annular condition because the display panel  5  is first disposed to the outside of a basically cylindrical spacer body  41  with substantially the entire bottom surface of the display panel  5  in contact with the spacer body  41 . Furthermore, because substantially the entire bottom surface of the display panel  5  is touching the spacer body  41 , the display panel  5  can be securely positioned by affixing only portions of both side edges and the middle portion, and the fixed area of the display panel  5  can thus be reduced. Distortion of the display panel  5  can thereby be reduced and image quality degradation can be prevented. 
   More specifically, the parts between the fixed side edge portions and middle portion are free because only the side edge portions and the middle portion of the display panel  5  are fixed in position. If a compressive force is then applied between the side edge portions and the middle portion, distortion of the display panel  5  caused by the area between the side edge portions and the middle portion flexing can be prevented. If only the side edge portions of the display panel  5  are secured, the middle portion of the display panel  5  in particular easily separates from the spacer body  41  due to the restoring force of the display panel  5 . By securing the middle part of the display panel  5  in addition to the side edge portions, however, this embodiment of the invention can attach the display panel  5  tightly to the spacer body  41 , and can thereby render the display panel  5  in a more stable condition. 
   (2) When the display panel  5  is secured by passing the edge portions in the middle part of the display panel  5  through channels in a holding part, the holding part applies pressure to the middle part of the display panel  5 . By attaching the middle part of the display panel  5  with double-sided tape T 1  instead of such a holding part, however, the invention reduces the force pressing on the display panel  5  and can thereby more effectively suppress distortion. The display panel  5  can also be easily installed because there is no need to pass the edge portions of the display panel  5  through channels. 
   (3) Movement of the display panel  5  can be effectively reduced and the display panel  5  can be disposed more securely as a result of rendering guide parts  414  for guiding the display panel  5  opposite the holding parts  411 A,  411 B on the outside surface of the spacer body  41 . 
   (4) Manufacturing variations can result in the length of the display panel  5  being slightly greater than the length around the outside of the spacer body  41 . By forming a gap S large enough to enable inserting the display panel  5  in the spacer  4 , however, part of the display panel  5  can be disposed in this gap S portion and below the spacer body  41 , and the display panel  5  can therefore be rendered more tightly to the spacer body  41 . 
   (5) Because a panel abutment  413  rises across the width of the spacer body  41  at one circumferential end part of the spacer body  41 , the display panel  5  can be easily positioned by sliding the distal end of the display panel  5  so that it contacts the panel abutment  413 . 
   (6) If the spacer  4  fits too tightly to the cylindrical part  311  due to variations in manufacture, the spacer  4  can still be easily fit to the cylindrical part  311  because the spacer  4  is elastically deformable and is formed with a break at one part in the circumference so that the gap at this break can be expanded. Cracking the spacer  4  by forcibly fitting the spacer  4  to the cylindrical part  311  can therefore be prevented. Distortion of the spacer  4 , and therefore the display panel  5 , resulting from fitting the spacer  4  to the cylindrical part  311  with excessive force can also be prevented. 
   Furthermore, because the spacer  4  is elastically deformable and is formed with a break at one part circumferentially, the spacer  4  can also absorb the force of impact and vibrations caused by dropping the timepiece  1 , for example, and the effect of such impact and vibration on the display panel  5  can be reduced. 
   (7) Furthermore, because channels  418  for accepting the protrusions  313  are formed on the inside surface of the spacer body  41  at positions corresponding to the protrusions  313  of the cylindrical part  311 , the spacer  4  and therefore the display panel  5  can be easily positioned to the frame  3  by fitting the protrusions  313  into the channels  418 . 
   The spacer  4  can also be easily expanded and the spacer  4  can be more easily fit onto the cylindrical part  311  because channels  418  are disposed to the inside surface of the spacer  4 . 
   (8) By rendering the cylindrical part  311  and the flange  312  in unison, the protrusions  313  function both to position the spacer  4  and to secure the back cover  32 , thereby simplifying the arrangement. 
   (9) By disposing the primary battery  10  between the two end parts of the electrophoretic display panel  5  that is wrapped around the outside surface of the body  31 , the thickness of the part where the display panel  5  and the primary battery  10  are disposed can be reduced and a thinner design can be achieved compared with an arrangement in which the display panel  5  and the primary battery  10  overlap each other. 
   (10) By covering the end parts of the display panel  5  including the primary battery  10  with the decorative plate  50 , the primary battery  10  and the battery storage unit  8  can be hidden so that they cannot be seen through the glass crystal  6 , and the appearance can therefore be improved. 
   (11) Decorativeness can be improved by rendering decoration including text, symbols, and patterns, for example, on the surface of the decorative plate  50 . By rendering a pattern using a complicated, advanced processing technique on the surface of the decorative plate  50 , for example, a luxurious appearance can be imparted. 
   (12) A uniform appearance can be achieved over the entire outside surface of the body  31  as a result of the decorative plate  50  and the display panel  5  curving around the outside of the body  31  and the decorative plate  50  covering the primary battery  10 . 
   (13) The decorative plate  50  can be easily positioned during assembly because the decorative plate position indication units  511  disposed to the display panel  5  can be illuminated. Furthermore, because the position indication units  511  can be turned off after the decorative plate  50  is positioned, a nice appearance can be achieved without exposing the position indication units  511 . 
   (14) The display panel  5  and the decorative plate  50  can be reliably secured and protected from scratches and soiling because the display panel  5  and the decorative plate  50  are covered by the glass crystal  6 . Furthermore, because the spacer  4 , the display panel  5 , and the glass crystal  6  are held between the flange  312  of the body  31  and the back cover  32 , the spacer  4 , the display panel  5 , and the glass crystal  6  can be reliably fixed to the frame  3  and can be easily assembled. 
   (15) The battery can be easily replaced by simply removing the back cover  32  from the body  31  and sliding the battery holder  81  out from the spacer  4  to access and replace the primary battery  10 . Dust, lint, and other foreign matter is also prevented from getting inside the frame  3  because disassembling the glass crystal  6  or spacer  4  to replace the battery is not necessary. 
   Embodiment 2 
   A second embodiment of the invention is described next.  FIG. 16  shows the electrical arrangement of a timepiece  1 A according to this embodiment of the invention.  FIG. 17  is a side section view of this timepiece  1 A. 
   This embodiment differs from the first embodiment in that it uses a secondary battery  10 A as the battery, locates the secondary battery  10 A in the position of the primary battery  10  in the first embodiment, and uses a photoelectric conversion means (solar battery)  50 A as the cover member. The basic arrangement of this embodiment is otherwise identical to the first embodiment. 
   More specifically, the timepiece  1 A has a solar battery  50 A that can convert light energy to electrical energy, and has a secondary battery  10 A for storing the electrical energy produced by the solar battery  50 A. As shown in  FIG. 16  the solar battery  50 A and the secondary battery  10 A are electrically connected to the controller  71 . 
   As shown in  FIG. 17 , the spacer  4 B includes the spacer body  41  and a secondary battery holding member  43 A, and the secondary battery  10 A is held in this secondary battery holding member  43 A. The secondary battery  10 A is located between the ends of the display panel  5  in the same way as the primary battery  10  in the first embodiment. 
   The solar battery  50 A is a two layer structure including the main solar cell  51 A and a support member  52 A, and is disposed along the outside of the body  31 . The main solar cell  51 A is a flexible thin film. Similarly to the display panel  5 , the support member  52 A is shaped to conform to the outside surface of the cylindrical part  311  of the body  31 . The main solar cell  51 A is affixed to the outside surface of the support member  52 A. Similarly to the decorative plate  50  in the first embodiment, the solar battery  50 A is disposed between the glass crystal  6  and the cylindrical part  311  of the body  31 , and covers the secondary battery  10 A and both ends of the display panel  5 . 
   The solar battery  50 A converts light energy to electrical energy in this configuration. The resulting electrical energy is stored in the secondary battery  10 A and supplied as needed from the secondary battery  10 A to other parts. 
   13. Effect of this Embodiment of the Invention 
   This embodiment of the invention affords the following effects in addition to the effects (1) to (14) of the first embodiment described above. 
   By providing a solar battery  50 A and a secondary battery  10 A, electrical energy can be constantly supplied even if the electrical energy stored in the secondary battery  10 A is supplied to other parts because the electrical energy newly produced by the solar battery  50 A can be stored in the secondary battery  10 A. Compared with an arrangement that uses a primary battery, this embodiment eliminates the need to regularly replace the battery and thereby reduces the burden on the user. There are also no depleted waste batteries to throw away, and the timepiece  1 A is therefore environmentally friendly. 
   Furthermore, because the main solar cell  51 A is a flexible thin film and the main solar cell  51 A can be disposed to the outside surface of the support member  52 A, the thickness of the solar battery  50 A can kept thin. The thickness of the timepiece  1 A where the solar battery  50 A is located can therefore also be thin, and an excellent appearance can be achieved. 
   14. Variations of the Invention 
   The invention is not limited to the foregoing embodiments and variations and improvements that can achieve the same purpose as the invention are included within the scope of this invention. 
   For example, holding parts  411 A,  411 B are disposed to the spacer in the foregoing embodiments, but a spacer  4 A having plurality of holding parts  411 C,  411 D can be used as a variation of this spacer.  FIG. 18  is an oblique view of a spacer  4 A according to such a variation of the invention. As shown in  FIG. 18  the spacer  4 A is for holding the display module  2  in a curved tubular shape, and includes a flange-side member  41 A, a back-cover-side member  41 B, and a holder retaining part  43  for storing the battery holder  81 . The flange-side member  41 A and the back-cover-side member  41 B are non-continuous rings having a break in one part of the ring. A plurality of holding parts  411 C,  411 D for retaining the display module  2  are formed along an edge of the side members  41 A and  41 B. 
   As shown in  FIG. 18 , the holder retaining part  43  is substantially C-shaped and supports a similarly C-shaped flat battery holder  81  so that the battery holder  81  can slide parallel to axis A. The sides of the flange-side member  41 A and the back-cover-side member  41 B perpendicular to axis A are bonded together so that the non-continuous parts align, and the holder retaining part  43  is installed to this break in the side members. 
   The battery holder  81  described below for holding a primary battery  10  is supported in the holder retaining part  43  so that the battery holder  81  can slide along axis A. When the battery holder  81  is disposed in the space enclosed by the spacer  4 A and the frame  3  and glass crystal  6 , the primary battery  10  can be replaced by removing the back cover  32  and sliding the battery holder  81  towards the back cover  32 . 
   Decorative plate position indication units  511  are disposed to the display panel  5  in the embodiment described above, but another aspect of the invention renders tabs  44  and  45  projecting to the inside of holding parts  411 E and  411 F as the arrangement for positioning the decorative plate  50 .  FIG. 19  is a plan view showing the position where the decorative plate  50  is disposed in a timepiece according to this aspect of the invention. 
   As shown in  FIG. 19  the decorative plate  50  can be positioned in the circumferential direction by causing the circumferential end parts of the decorative plate  50  to contact the tabs  44  and  45 . This enables positioning the decorative plate  50  easily in a short time during the assembly process, and makes assembly more efficient. 
   The spacer  4  is formed in the above embodiments with a break in the circumference so that the spacer  4  can be elastically deformed, but the spacer does not require such a break. 
   If a break is not provided in the spacer, a slit can be rendered in the spacer so that the excess part of the display panel  5  can be passed through the slit and disposed in the space between the spacer and the cylindrical part  311 . 
   In addition, when a break is not provided in the spacer, grooves that can receive the protrusions  313  and run from edge to edge on the inside circumference surface of the spacer are formed at positions corresponding to each of the protrusions  313  on the cylindrical part  311 . After aligning the grooves with the protrusions  313 , the spacer is then slid towards the flange  312  to fit the spacer onto the cylindrical part  311 . 
   The protrusions  313  are formed on the edge part of the cylindrical part  311  and function both for positioning and for fastening the back cover  32 , but the protrusions can be used only for positioning. If the protrusions are used only for positioning, they can be disposed at suitable positions on the outside of the cylinder part. The protrusions can also be omitted. 
   The frame  3  includes two parts, a substantially L-shaped body  31  and back cover  32 , in the foregoing embodiments, but the cylinder part rendering the body and the flange part can be manufactured separately such that the frame is composed of three parts, the cylinder part, the flange part, and the back cover. 
   The battery storage unit  8  is disposed to an edge part of the spacer body  41  in the above embodiments, but the battery storage unit can be located between the spacer and the cylinder part. 
   The cylinder part (cylindrical part  311 ) is circular in the above embodiments, but can be a polygonal tube instead. 
   The display panel  5  is secured at both ends by holding parts  411 A,  411 B having a pair of channels  412  and is secured in the middle by double-sided tape T 1 , but the middle part can alternatively be secured by a holding part having a pair of channels. The display panel  5  is also not limited to being secured at both ends and the middle, and can be secured at multiple other locations. 
   The display panel  5  can also be adhesively attached to the spacer  4  with adhesive. 
   A glass crystal  6  is used as the transparent member in the foregoing embodiments of the invention, but any member, such as a transparent plastic cover, that enables seeing the display panel can be used. A colored member can be used if it is also transparent. 
   The first embodiment of the invention is described using by way of example a timepiece  1  having a decorative plate  50  and a frame  3  of a prescribed diameter, but can also be rendered as timepieces of different sizes having, for example, a frame of a different diameter, a decorative plate having a circumferential length adjusted for the diameter of the frame, and the same display panel  5  as in the first embodiment. To assemble this timepiece the display panel  5  is disposed to the outside of the frame in the same way as in the first embodiment, and the decorative plate is then positioned to cover both end parts of the display panel  5 . This arrangement enables using a common display panel  5  with frames  3  of different diameters by simply changing the length of the decorative plate  50  in the circumferential direction. Common parts can thus be used for different products, and the cost can therefore be reduced. 
   The spacer  4  includes a flange-side member  41 A and a back-cover-side member  41 B in the foregoing embodiments of the invention, but these can be formed as a single part. 
   The display device can further alternatively be rendered with the battery overlapping the display panel and the solar cell used as the cover member covering the ends of the display panel. 
   The decorative plate  50  used as a cover member in the first embodiment of the invention extends above both end parts of the electrophoretic display panel  5  and is formed to cover both end parts, but in the present invention must only be shaped to cover at least the primary battery  10 . However, by forming the display panel  5  to cover both end parts of the display panel  5 , the wiring member C 1  at the end of the display panel  5  can also be reliably covered and the design can be improved. 
   The foregoing embodiments of the invention are described using an electrophoretic display panel by way of example as the display panel, but the display panel of the invention can, for example, be an organic EL panel instead. More specifically, any band-shaped display panel that is also flexible can be used. 
   The second embodiment of the invention is described using a secondary battery  10 A by way of example as the battery and the secondary battery  10 A can be charged by providing a common charging terminal in the frame or by supplying power wirelessly using an electromagnetic induction method, for example. 
   The secondary battery  10 A used in the second embodiment can also be supported and stored so that the battery can slide when the back cover is removed in the same way as the primary battery  10  in the first embodiment. This arrangement makes replacing the secondary battery  10 A simple and helps prevent foreign matter from entering the frame  3  when the battery is replaced. 
   The invention is described above using a timepiece by way of example, but the invention can rendered in a cell phone, a digital camera, or a personal digital assistant (PDA) device, for example. More specifically, the display device of the invention is not limited to displaying time, and can function to display various types of information. The display device is also not limited to being worn as a bracelet, and can be placed or worn as desired, including suspended on a chain from a wall, for example. 
   The best mode and method of achieving the invention are described above, but the invention is not limited to the foregoing embodiments. More specifically, the invention is shown and described with reference to particular embodiments of the invention, but the form, quantity, and other details of the foregoing embodiments can be varied in many ways by a person skilled in the related art without departing from the technical concept and scope of the present invention. 
   Therefore, because the foregoing description of specific shapes, quantities, and other details is given by way of example for easily understanding the invention and does not limit the invention, any description using these parts from which these shape, quantity, and other limitations are removed in part or in full are included in the scope of the invention. 
   The entire disclosure of Japanese Patent Application Nos: 2006-275848, filed Oct. 6, 2006 and 2007-023365, filed Feb. 1, 2007 are expressly incorporated by reference herein.