Indication device

Abstract

To provide a retractable display device that can be miniaturized and also features a free-stop mechanism. [Solution] The display device 10 includes a first axis 12 and a second axis 14 arranged in parallel, a sheet body 16 wound over the first axis 12 and the second axis 14, a first constant-load spring 18A that biases the first axis 12 in the direction in which the sheet body 16 is wound, a second constant-load spring 18B that biases the second axis 14 in the direction in which the sheet body 16 is wound, and an OLED 46 that is wound onto the first axis 12 in a stacked state with the sheet body 16 when the sheet body 16 is wound onto the first axis 12, and is unwound from between the first axis 12 and the second axis 14 when the sheet body 16 is unwound from the first axis 12 to the second axis 14. The unwinding of the OLED 46 stops at an arbitrary position based on the torque generated by the first constant-load spring 18A and the second constant-load spring 18B.

Description

Technical Field

[0001] The present invention relates to a retractable display device.

Background Art

[0002] Patent Document 1 discloses a retractable display device. In this display device, a display unit is wound and stored inside a stationary housing, and the display unit is moved up and down under the action of a motor using a link mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although a retractable display device can be stored in a small area and volume, the display device of Patent Document 1 has a power mechanism such as a link mechanism and a motor, so it is large as a whole. In addition, if a retractable display device is made a free-stop type that can maintain an arbitrary amount of unwinding by taking advantage of its characteristics, its applications will expand.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a retractable display device that can be miniaturized and can realize a free-stop type.

Means for Solving the Problems

[0006] To solve the above-mentioned problems and achieve the objective, a display device according to an aspect of the present invention comprises a first axis and a second axis arranged in parallel, a sheet body wound over the first axis and the second axis, a first constant-load spring that biases the first axis in the direction in which the sheet body is wound, a second constant-load spring that biases the second axis in the direction in which the sheet body is wound, and an OLED that is wound onto the first axis in a stacked state with the sheet body when the sheet body is wound onto the first axis, and unwound from between the first axis and the second axis when the sheet body is unwound from the first axis to the second axis. [Effects of the Invention]

[0007] The display device according to the present invention can be miniaturized and can also be operated in a free-stop manner. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view of a display device according to an embodiment of the present invention, in which a flexible display element including an OLED is extended by a predetermined amount. [Figure 2] Figure 2 is a schematic perspective view of the display device with the flexible display unit housed inside. [Figure 3] Figure 3 is a schematic perspective view of a constant-load spring. [Figure 4] Figure 4 is a partially enlarged exploded perspective view of the flexible display unit. [Figure 5] Figure 5 is a schematic perspective view of a part of the display device, seen from a diagonal rearward angle. [Figure 6] Figure 6 is a schematic cross-sectional view of a flexible display unit. [Figure 7] Figure 7 shows the back sheet. [Figure 8] Figure 8 is a schematic cross-sectional side view of the display device. [Figure 9] Figure 9 is a schematic cross-sectional side view of the display device according to the first modified example. [Figure 10] Figure 10 is a schematic cross-sectional side view of a display device according to a second modified example. [Figure 11] Figure 11 is a schematic perspective view of a display device according to a second modified example. [Modes for carrying out the invention]

[0009] Embodiments of the display device according to the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to these embodiments.

[0010] Figure 1 is a schematic perspective view of a display device 10 according to an embodiment of the present invention, in which the flexible display body 22, including the OLED 46, is extended by a predetermined amount. Figure 2 is a schematic perspective view of the display device 10 in which the flexible display body 22 is retracted.

[0011] The display device 10 includes a first shaft 12 and a second shaft 14 arranged in parallel, a sheet body 16 wrapped around the first shaft 12 and the second shaft 14, a first constant-load spring 18A, a second constant-load spring 18B, and a flexible display body 22. The flexible display body 22 can be wound up and unwound relative to the first shaft 12. The first shaft 12 and the second shaft 14 have a circular cross-section, but do not necessarily have to be circular. Although not shown in the figures, the display device 10 is equipped with a cover that covers the first shaft 12, the second shaft 14, the first constant-load spring 18A, and the second constant-load spring 18B. The flexible display body 22 is wound up and unwound through a slit formed on the upper surface of the cover.

[0012] In each figure, the axial directions of the first axis 12 and the second axis 14 are shown as the X direction, and the direction in which the flexible display body 22 extends from the first axis 12 is shown as the Y direction. The Y direction is slightly inclined with respect to the vertical direction, and in this embodiment, the angle θ between the Y direction and the vertical direction is about 15°. The X direction and the Y direction are orthogonal. The side of the flexible display body 22 with the display surface is considered the front, and the side with the non-display surface is considered the back. When the display device 10 is placed on a desk, the display surface of the flexible display body 22 is positioned to face the user's face almost directly. However, the display device 10 does not necessarily need to be placed on a desk; for example, it can be used as a handheld device like a tablet terminal.

[0013] The X-width of the first axis 12 and the second axis 14 is moderately longer than that of the flexible display body 22, and they are pivotally supported by the left and right side plates 24a and 24b. The side plates 24a and 24b are erected from both ends of the plate 26. The second axis 14 is positioned moderately above and slightly behind the first axis 12, and the common tangent direction connecting the rear surface of the first axis 12 and the front surface of the second axis 14 coincides with the Y-direction.

[0014] A control unit 28 is provided in the hollow section of the first axis 12. The display device 10 can be connected to external devices 30 by wire or wireless connection. Examples of external devices 30 include a keyboard 30a, mouse 30b, I / O port 30c, battery 30d, and personal computer 30e. The personal computer 30e becomes a dual-monitor setup when the display device 10 is connected. The display device 10 is powered by a primary battery, a secondary battery, or commercial AC power. A sensor may be provided to detect the amount of rotation of the first axis 12, and the control unit 28 may read this data.

[0015] The sheet body 16 is made of a fabric such as nylon, is flexible, has an appropriate tensile strength, and has little elongation. The sheet body 16 is wound around the flexible display body 22 in a laminated state with respect to the first axis 12, extending from the rear surface of the first axis 12 to the front surface of the second axis 14, and is wound around the second axis 14 separately from the flexible display body 22. Therefore, when the second axis 14 rotates clockwise in FIGS. 1 and 2, the sheet body 16 is wound around the second axis 14, and the first axis 12 rotates counterclockwise to unwind the sheet body 16. Conversely, when the first axis 12 rotates clockwise, the sheet body 16 is wound around the first axis 12, and the second axis 14 rotates counterclockwise to unwind the sheet body 16. Both ends of the flexible display body 22 are supported by a strip material 52 described later and are maintained independently in a straight line. However, the sheet body 16 supports the rear surface of the flexible display body 22 over a relatively large area between the two strip materials 52, further stabilizing the independence.

[0016] A first constant load spring 18A that biases the first axis 12 in the direction in which the first axis 12 winds up the sheet body 16, that is, the clockwise direction in FIGS. 1 and 2, is provided on the first axis 12. A second constant load spring 18B that biases the second axis 14 in the direction in which the second axis 14 winds up the sheet body 16, that is, the clockwise direction in FIGS. 1 and 2, is provided on the second axis 14. The first constant load spring 18A and the second constant load spring 18B are also typically referred to as the constant load spring 18. Since the first axis 12 and the second axis 14 are each biased in the direction of winding up the sheet body 16 by the constant load spring 18, an appropriate tension is generated in the sheet body 16 and it does not bend. Further, the sheet body 16 acts such that when one of the first axis 12 and the second axis 14 winds up, the other unwinds, and when one unwinds, the other also unwinds.

[0017] The first constant load spring 18A and the second constant load spring 18B are each located between the flexible display body 22 and the side plate 24a and are arranged side by side in the front-rear direction. The first constant load spring 18A and the second constant load spring 18B may be arranged separately on the left and right of the flexible display body 22.

[0018] Figure 3 is a schematic perspective view of the constant-load spring 18. In Figure 3, some parts are shown with dashed lines. The constant-load spring 18 will be described with reference to Figures 1, 2, and 3. The constant-load spring 18 is provided at the right ends of the first shaft 12 and the second shaft 14. The constant-load spring 18 has an elastic band 34, a first pulley 36, and a second pulley 38. The first pulley 36 of the first constant-load spring 18A is provided on the first shaft 12, and the first pulley 36 of the second constant-load spring 18B is provided on the second shaft 14. The second pulley 38 is pivotally supported on the pulley shaft 38a. The pulley shaft 38a is pivotally supported on the side plate 24a. In the first constant-load spring 18A, the pulley shaft 38a is above the first shaft 12, and in the second constant-load spring 18B, the pulley shaft 38a is below the second shaft 14, resulting in a good layout balance.

[0019] The elastic band 34 is a metal spring material that has a flexural elasticity that causes it to spiral in its natural state, similar to a coiled spring. The elastic band 34 hardly stretches in the tensile direction. The first pulley 36 is wound in the opposite direction to the spiral direction of the elastic band 34 in its natural state. The second pulley 38 winds the elastic band 34 that has been unwound from the first pulley 36 in the direction of its natural spiral. Such a constant-load spring 18 always exerts a constant elastic force regardless of the amount of elastic band 34 unwound, thereby imparting rotational force to the first pulley 36.

[0020] Figure 4 is a partially enlarged exploded perspective view of the flexible display unit 22. Figure 5 is a schematic perspective view of a part of the display device 10 viewed from the rear at an angle. Figure 6 is a schematic cross-sectional view of the flexible display unit 22. Figure 7 shows the backsheet 50. The circle in Figure 7 is a partially enlarged view of the backsheet 50. The flexible display unit 22 is a laminate in which a polyimide sheet 40, a polarizing sheet 42, a touch sensor 44, an OLED (Organic Light Emitting Display) 46, a PET (Polyethylene Terephthalate) sheet 48, and a backsheet 50 are fixed together with adhesive tape or the like. Of these, the touch sensor 44 and others may be omitted depending on the design conditions. The OLED 46 is thin and lightweight, has low power consumption, and is characterized by excellent contrast and responsiveness. In addition, although the OLED 46 is flexible and can be rolled up, its bending elasticity is relatively strong and it has the property of returning to a flat state if there is no external force. In this embodiment, the size of the OLED 46 is, for example, about 30 inches. In Figure 1, the front side of the OLED 46 is the display surface and the rear side is the non-display surface.

[0021] The backsheet 50 is attached to the rear side of the flexible display unit 22, that is, the non-display side of the OLED 46. In Figure 4, the backsheet 50 is explicitly shown separated from the flexible display unit 22. The backsheet 50 is made of a moderately hard and thin material, for example, stainless steel with a thickness of 150 μm. Numerous elongated holes 50a, which are long in the X direction, are formed almost entirely on the backsheet 50. The elongated holes 50a are aligned in the X direction and form multiple rows in the Y direction. The elongated holes 50a are arranged alternately in the X direction between adjacent rows. Such a backsheet 50 has the property of stretching in the Y direction, making it easy to wind around the first axis 12, and is strong in the X direction.

[0022] When the flexible display unit 22 is stored for a long period of time wound up on the first axis 12, it has been observed that it tends to develop a convex, arc-shaped curl, as shown by the dashed line in Figure 4. This phenomenon is thought to occur because when the OLED 46 is returned to its flat state, the outermost film is pulled vertically, causing it to contract slightly horizontally. The backsheet 50 prevents this curling and keeps the flexible display unit 22 in a nearly flat state.

[0023] A pair of strips 52 are provided at both ends of the flexible display body 22, extending almost the entire length in the Y direction. The strips 52 and the flexible display body 22 are slightly separated. The gap 54 between the strips 52 and the flexible display body 22 is, for example, about 1 mm. The strips 52 have an arc-shaped cross-section similar to a metal measuring tape called a convex, and can be wound up together with the flexible display body 22 on the first axis 12, and can maintain the flexible display body 22 in a straight line when unwinding. In Figure 1, the strips 52 are in a convex arc shape facing backward.

[0024] The flexible display unit 22 and the strip material 52 are fixed together by multiple fixing materials 56. The fixing materials 56 are thin, somewhat elongated adhesive materials, and multiple pieces are provided between the flexible display unit 22 and the strip material 52 at narrow intervals in the Y direction. There are about 10 pieces of fixing material 56 on each side of the flexible display unit 22. The fixing material 56 is strong in tension in the X direction but expandable in the Y direction, such as cloth duct tape. Since the expansion and contraction of each fixing material 56 does not perfectly follow the expansion and contraction of the backsheet 50, it is better to make the width in the Y direction as narrow as possible. In other words, dividing the fixing material 56 into multiple pieces rather than providing one long piece in the Y direction makes it easier for the entire Y direction to expand and contract. Therefore, the back of the flexible display unit 22 can absorb the expansion and contraction in the Y direction when unwinding and winding, and the flexible display unit 22 is not distorted.

[0025] An operating bar 58 is fixed to the upper end of the flexible display body 22 and the strip material 52. The operating bar 58 is shaped and thick enough to be easily grasped by hand. The flexible display body 22 (see Figure 1), unwound from the first shaft 12, is kept in a flat position by being surrounded on all four sides by the left and right strip materials 52, the upper operating bar 58, and the lower first shaft. The operating bar 58 contacts the upper surface of the cover when the flexible display body 22 is being wound up, acting as a stopper to prevent it from being wound up too much relative to the first shaft 12. As a stopper when the flexible display body 22 is being unwound, for example, an arm that moves in conjunction with the first shaft 12 at a reduced speed can contact the upper surface of the plate 26 to limit its movement. Such a stopper mechanism can also be applied when winding up.

[0026] As shown in Figure 6, the flexible display unit 22 is a laminate consisting of a polyimide sheet 40, a polarizing sheet 42, a touch sensor 44, an OLED 46, a PET sheet 48, and a back sheet 50. When wound around the first axis 12, a displacement of length L occurs at the end due to the path difference between the inner and outer circumferences. If this displacement is excessive, delamination may occur. The length L is determined by the number of times the flexible display unit 22 is wound around the first axis 12. The length L can be reduced by making the first axis 12 larger in diameter and reducing the number of windings, but this increases the overall size. To make the length L sufficiently small for practical use without causing delamination, it is appropriate to limit the number of windings of the flexible display unit 22 to three or less. Also, if the first axis 12 is small in diameter, the first constant-load spring 18A for winding must be made larger. Under these conditions, in this embodiment, the winding length of the flexible display body 22 is approximately 340 mm, while the diameter of the first shaft 12 is 40 mm (radius r1 = 20 mm in Figure 8), and the number of windings is 2.7.

[0027] Incidentally, as mentioned above, the OLED 46 of the flexible display 22 has the property of returning to a flat state if there is no external force. The strip material 52 has the same property. For this reason, it is difficult to wrap the flexible display 22 and the strip material 52 around the first axis 12 as they are. It is conceivable to provide a cylinder around the first axis 12 to prevent the flexible display 22 and the strip material 52 from spreading out, but a large amount of friction will be generated between the flexible display 22, which tries to spread out, and the cylinder, requiring a large force to unwind and wind up.

[0028] In the display device 10 according to this embodiment, a sheet body 16 wrapped around a first axis 12 and a second axis 14 is subjected to appropriate tension by a first constant-load spring 18A and a second constant-load spring 18B. The flexible display body 22, including the OLED 46, is wound onto the first axis 12 in a stacked state with the sheet body 16, and as the sheet body 16 is unwound from the first axis 12 to the second axis 14, the flexible display body 22 is unwound from between the first axis 12 and the second axis 14. Therefore, the force that would cause the OLED 46 to return to a planar state is corrected by the sheet body 16, preventing it from spreading out, and allowing it to be wound onto the first axis 12 together with the sheet body 16 with almost no gaps.

[0029] The second axis 14 supports the rear surface of the flexible display body 22. In order to stably support the flexible display body 22, it is desirable that the distance between the first axis 12 and the second axis 14 be a certain distance, for example, about 1 to 2 times the diameter of the first axis 12. Since there is a sheet body 16 between the second axis 14 and the flexible display body 22 that displaces synchronously with the flexible display body 22, the flexible display body 22 does not slide against the second axis 14.

[0030] The flexible display unit 22 is self-standing and is maintained upright by the strip material 52 when the operating bar 58 is grasped and lifted upwards. Furthermore, the unwinding of the flexible display unit 22 is a free-stop type that stops at any position based on the torque generated by the first constant-load spring 18A and the second constant-load spring 18B. More specifically, since forces due to the bending rigidity of the OLED 46 and frictional forces act on the sheet body 16, the first constant-load spring 18A and the second constant-load spring 18B are set to take these into consideration.

[0031] Figure 8 is a schematic cross-sectional side view of the display device 10. Further explanation will be given with reference to Figure 8. T1 is the clockwise torque biased on the first shaft 12 by the first constant-load spring 18A. T2 is the clockwise torque biased on the second shaft 14 by the second constant-load spring 18B. r1 is the radius of the first shaft 12. r2 is the radius of the second shaft 14. F1 is the downward force applied by the first shaft 12 to the sheet body 16, where F1 = T1 / r1. F2 is the upward force applied by the second shaft 14 to the sheet body 16, where F2 = T2 / r2. F3 is the upward force resulting from the property of the OLED 46 and strip material 52 to return to a planar state, and is approximately constant in magnitude, similar to the constant-load spring 18. F3 is sufficiently small compared to F1 and F2.

[0032] As described above, the radius r1 of the first shaft 12 is determined by conditions such as the number of windings of the flexible display body 22. Also, F1 is determined by the force required to wind the flexible display body 22 onto the first shaft 12 without any gaps. Then T1 is determined as F1 × r1, and the first constant load spring 18A is selected based on T1. The torque generated by the constant load spring 18 is determined by the width of the elastic band 34 (see Figure 3), etc. In order to make the flexible display body 22 a free-stop type, F1 = F2 + F3 is used to balance it. As described above, F3 is an almost constant value, so F2 is determined as F2 = F1 - F3. Since T2 = F2 × r2, if the radius r2 of the second shaft 14 is reduced, the torque T2 required for the second constant load spring 18B will also be reduced. In other words, it is preferable to reduce the diameter of the second shaft 14 and miniaturize the second constant load spring 18B. In the display device 10, the second axis 14 has a smaller diameter than the first axis 12, thereby miniaturizing the second constant-load spring 18B.

[0033] In the display device 10, balance is achieved by setting F1 = F2 + F3, but in reality, due to individual differences, perfect balance is not achieved, and the flexible display body 22 stops at any desired position due to the small frictional forces of each part. This small frictional force can occur naturally, for example, between the first shaft 12 and the side plates 24a and 24b, but an intentional friction element may also be provided. The torque generated by the intentionally provided friction element is sufficiently small compared to the above torques T1 and T2. Bearings may be provided between the first shaft 12 and the side plates 24a and 24b.

[0034] The flexible display unit 22 is wound up together with the sheet body 16 on the first shaft 12 by gripping the operating bar 58 and pushing it down. In terms of design, the first constant-load spring 18A and the second constant-load spring 18B are balanced, so that the user can unwind and wind up the flexible display unit 22 with a sufficiently small force. The force required to unwind and wind up the flexible display unit 22 is almost constant regardless of the amount unwinded.

[0035] The strip material 52 allows the flexible display unit 22 to be kept in a horizontally extended position. If the flexible display unit 22 is to be extended downwards, the strip material 52 may be omitted.

[0036] In the display device 10, a tension of F2 is constantly applied to the sheet body 16, allowing the flexible display body 22 to be wound up and unwound without recovering to a flat state. This also supports the back of the flexible display body 22, eliminating the need for complex structures such as self-supporting links other than the strip material 52, thus reducing weight.

[0037] The display device 10 can be housed in a significantly smaller space by winding the flexible display body 22 onto the first axis 12, and it does not require any power mechanisms such as linkages or motors. Therefore, it can be miniaturized and is suitable for mobile applications. However, depending on the specifications, it may be automated using a motor.

[0038] Figure 9 is a schematic cross-sectional side view of the display device 10A according to the first modified example. In the above-described display device 10, the sheet body 16 is wrapped around the rear surface of the first shaft 12 and extends to the front surface of the second shaft 14, as shown in Figure 8, and the first shaft 12 and the second shaft 14 are biased clockwise. However, in the display device 10A, the sheet body 16 is wrapped around the rear surface of the first shaft 12 and extends to the rear surface of the second shaft 14, and the first shaft 12 is biased clockwise and the second shaft 14 is biased counterclockwise.

[0039] In other words, the first constant-load spring 18A biases the first shaft 12 in the direction in which the sheet body 16 is wound up, and the second constant-load spring 18B biases the second shaft 14 in the direction in which the sheet body 16 is wound up. The sheet body 16 is configured such that when one of the first shafts 12 and the second shaft 14 is wound up, the other is unwound, and when one is unwound, the other is unwound. In the display device 10A, the back of the flexible display body 22 is supported by idler rollers 60. In the example in Figure 9, two idler rollers 60 are provided, slightly separated in the Y direction, but there may be one or more than three.

[0040] Figure 10 is a schematic cross-sectional side view of the display device 10B according to the second modified example. Figure 11 is a schematic perspective view of the display device 10B. In the display device 10B, the second axis 14 is positioned in front of the first axis 12, and the sheet body 16 is wrapped around from the lower surface of the first axis 12 to the upper surface of the second axis 14. The display device 10B has a housing cover 62 that covers the first axis 12 and the second axis 14. In Figure 11, the constant-load spring 18 and other components are omitted.

[0041] In the display device 10B, the winding direction of the flexible display body 22 and the sheet body 16 relative to the first axis 12 and the second axis 14 is reversed compared to the display device 10. Therefore, the directions of the torques T1 and T2 relative to the first axis 12 and the second axis 14 are also reversed, being counterclockwise in both cases.

[0042] In the example above (see Figure 8), the flexible display body 22 extended from the rear surface of the first axis 12, whereas in the display device 10B, it extends from the front. The flexible display body 22 extends in the Y direction from a slit 64 formed in the housing cover 62. The slit 64 is formed between the upper wall 66 that covers the upper part of the first axis 12 and the support piece 68 that supports the flexible display body 22 at the front.

[0043] The support pieces 68 are positioned diagonally forward from the first axis 12 and have an appropriate width in the Y direction. There is a pair of support pieces 68, one on the left and one on the right, and each abuts against the front surface of the strip material 52 to support its self-supporting position, preventing the flexible surface 22 from tipping forward. The slits 64 are formed on the left and right sides corresponding to the support pieces 68. The contact surface of the support piece 68 against the strip material 52 should be an arc-shaped surface that matches the shape of the strip material 52.

[0044] Since the support piece 68 supports only the strip material 52, it does not obstruct the display area of ​​the flexible display body 22. In other words, the rectangular area 70 (shown by dashed lines) between the left and right support pieces 68 can be effectively utilized as a display area, and the area up to the rotation center of the first axis 12 can be used as a display. Depending on the conditions, a transparent plate may be provided in the rectangular area 68 to support the flexible display body 22 more securely. In addition, if necessary, an idler roller 60 as shown in Figure 9 may be appropriately provided to adjust or support the orientation of the flexible display body 22. The inclination angle of the support piece 68 may be variable, as shown by dashed lines in Figure 10.

[0045] In the example shown in Figure 8, the forces F1, F2, and F3 lie on a straight line and can be treated as scalar quantities. However, in the examples shown in Figures 9 to 11, the directions are different, so they are treated as vector quantities. Although they differ in this respect, the same symbols are used in each figure for ease of comparison.

[0046] The present invention is not limited to the embodiments described above, and can be freely modified without departing from the spirit of the invention. [Explanation of Symbols]

[0047] 10 Display device 12 1st axis 14 2nd axis 16 sheets 18A First constant load spring 18B Second constant load spring 22 Flexible display unit 24a,24b side plate 26 plates 28 Control Unit 30 External equipment 34 Elastic band 36. First Pulley 38. Second pulley 46 OLED 50 Backseat 50a long hole 52 strip material 54 gaps 56 Fixing material 58 Control Bar

Claims

1. The first and second axes are arranged in parallel, A sheet body wrapped around the first axis and the second axis, A first constant-load spring biases the first shaft in the direction in which the sheet body is wound, A second constant-load spring biases the second shaft in the direction in which the sheet body is wound, The sheet body is wound onto the first shaft so as to be wound onto the first shaft in a laminated state with the sheet body, and the OLED is unwound from between the first shaft and the second shaft so as the sheet body is unwound from the first shaft to the second shaft, It has, The unwinding of the OLED stops at any position based on the torque generated by the first constant-load spring and the second constant-load spring. A display device characterized by the following features.

2. In the display device according to claim 1, The unwinding of the OLED is balanced by the first constant-load spring, the second constant-load spring, the force resulting from the bending rigidity of the OLED, and friction, and stops at any desired position. A display device characterized by the following features.

3. In the display device according to claim 1, The strip material is provided on both edges along the unwinding extension direction relative to the OLED, and is capable of being wound together with the OLED on the first axis, and maintains the OLED in a straight line when unwinding. A display device characterized by the following features.

4. In the display device according to claim 3, Multiple OLEDs and strip materials are provided along the unwinding extension direction and are fixed by a fixing member that is expandable and contractible in the extension direction. A display device characterized by the following features.

5. In the display device according to claim 1, The back sheet has a number of elongated holes that are long in the axial direction of the first and second axes formed on almost its entire surface. The back sheet is attached to the non-display surface of the OLED. A display device characterized by the following features.

6. In the display device according to claim 1, The second shaft has a smaller diameter than the first shaft. A display device characterized by the following features.

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