The present application claims priority from Japanese application JP2011-229641 filed on Oct. 19, 2011, the contents of which are hereby incorporated by reference into this application.
1. Field of the Invention
The present invention relates to a display device.
2. Description of the Related Art
Micro-electromechanical system displays (MEMS displays) are displays expected to replace liquid crystal displays (see JP 2008-197668 A). Unlike the liquid crystal shutter system using polarized light, these displays open and close the light transmission windows using a mechanical shutter system to thereby display an image.
The shutter has driven openings, and is arranged to be driven while being attached to a substrate. Another substrate provided with a light-blocking film is disposed so as to be opposed to this substrate, and the light-blocking film is provided with stationary openings. When driving the shutter, the light is transmitted if the driven openings and the stationary openings are matched each other, and the light is blocked if they are shifted from each other, which makes an ON-OFF action of one pixel possible.
In the MEMS display of the related art, it is not achievable to check how much the driven openings and the stationary openings are shifted from each other when the shutter blocks the light. Although the light can be blocked in a vertical direction providing the driven openings and the stationary openings are shifted from each other in the vertical direction, in order to prevent the light from being obliquely leaked, it is necessary to assure the shift amount set previously. Since the shift amount affects the view angle dependency of the contrast, and further, the light leakage might also be caused at worst if the displacement due to the bonding of the both substrates is large, it is important to make it possible to perform screening with an inspection.
The present invention has an object of providing a structure of making it possible to detect the shift amount between the driven openings and the stationary openings.
1. A display device according to the invention includes a first substrate having a light transmissive property, a light-blocking film provided to the first substrate, a second substrate having a light transmissive property, disposed so as to be opposed to the first substrate with a space, a plurality of shutters provided to the second substrate, and a plurality of drive sections provided to the second substrate, and adapted to move the respective shutters between a first position and a second position, an area where the first substrate and the second substrate overlap each other includes a display area and a peripheral area surrounding the display area, the plurality of shutters are arranged in the display area and the peripheral area, each of the shutters has at least one driven opening moving in conjunction with a movement of the shutter, a whole of the plurality of shutters has a plurality of the driven openings, the light-blocking film is formed in the display area and the peripheral area, the light-blocking film has a plurality of stationary openings in the display area so as to correspond to the driven openings in the display area, each of the shutters in the display area makes the driven opening and the stationary opening be communicated with each other to transmit light at the first position, and is disposed so that the driven opening and the stationary opening are shifted from each other to block the light at the second position, and the light-blocking film has, in the peripheral area, a dummy opening adapted to partially expose at least one of the shutters arranged in the peripheral area. According to the present invention, since the light is blocked if the shutter is located at the second position, it is not achievable to measure the shift amount between the driven opening and the stationary opening in the display area. However, if it is possible to measure the distance between the edge of the dummy opening and the driven opening in the peripheral area, the shift amount between the driven opening and the stationary opening can be detected in accordance with the distance measured.
2. In the display device according to Section 1, it is also possible that the plurality of driven openings are arranged with regularity in the entire display area and peripheral area, the plurality of stationary openings are arranged with regularity corresponding to the regularity of the plurality of driven openings, and in a case in which the plurality of shutters are located at the second position, a distance between the driven opening and an edge of the dummy opening in the peripheral area and a distance between the driven opening and a part of an edge of the stationary opening in the display area have a correlative relationship with each other.
3. In the display device according to Section 2, it is also possible that the edge of the dummy opening includes an edge formed of a part of an edge of the stationary opening, which is assumed to be arranged in the peripheral area with the regularity of the plurality of stationary openings.
4. In the display device according to any one of Sections 1 through 3, it is also possible that in a case in which the plurality of shutters are located at the second position, a distance between the driven opening and an edge of the dummy opening in the peripheral area and a distance between the driven opening and a part of an edge of the stationary opening in the display area are equal to each other.
5. In the display device according to any one of Sections 1 through 4, it is also possible that an edge of the dummy opening is a part of the stationary opening.
6. In the display device according to any one of Sections 1 through 5, it is also possible that the driven openings are each formed so as to extend in a direction intersecting with a direction between the first position and the second position, and in a case in which the shutter in the display area is located at the second position, the stationary opening in the display area is located at a position shifted from the driven opening in a direction between the first position and the second position.
7. In the display device according to Section 6, it is also possible that in a case in which the shutter in the peripheral area is located at the second position, an edge of the dummy opening is located at a position shifted from an edge of the driven opening in the direction between the first position and the second position.
8. In the display device according to Section 6, it is also possible that in the case in which the shutter in the peripheral area is located at the second position, an edge of the dummy opening is located at a position shifted from an edge of the driven opening in a direction in which the driven opening extends.
9. In the display device according to Section 6, it is also possible that an edge of the dummy opening includes a first edge and a second edge, in a case in which the shutter in the peripheral area is located at the second position, the first edge is located at a position shifted from an edge of the driven opening in the direction between the first position and the second position, and in the case in which the shutter in the peripheral area is located at the second position, the second edge is located at a position shifted from an edge of the driven opening in a direction in which the driven opening extends.
10. In the display device according to any one of Sections 1 through 6, it is also possible that the shutters in the peripheral area include a first shutter and a second shutter, and the light-blocking film is formed so as to always cover a whole of the driven opening of the first shutter irrespective of the position of the first shutter, and to expose a part of an edge of the driven opening of the second shutter from the dummy opening in a case in which the second shutter is located at the second position.
11. In the display device according to Section 10, it is also possible that in a case in which the second shutter is located at the second position in the peripheral area, an edge of the light-blocking film overlaps a substrate of the second shutter.
12. In the display device according to Section 10, it is also possible that in a case in which the second shutter is located at the second position in the peripheral area, an edge of the light-blocking film overlaps the driven opening of the second shutter.
13. In the display device according to Section 10, it is also possible that in a case in which the second shutter is located at the second position, an edge of the light-blocking film includes a first edge overlapping a substrate of the second shutter and a second edge overlapping the driven opening of the second shutter.
14. In the display device according to any one of Sections 1 through 3, it is also possible that the display area and the peripheral area are each formed to have a rectangular shape, and the dummy opening is provided to each of four corners of the peripheral area.
Some embodiments of the invention will hereinafter be explained with reference to the accompanying drawings.
The light-blocking film 12 has a plurality of stationary openings 22 in the display area 18. The stationary opening 22 is a slit elongated in one direction. The plurality of stationary openings 22 are arranged to extend in parallel to each other. The plurality of stationary openings 22 are arranged with regularity. For example, a predetermined number (three in
The light-blocking film 12 has dummy openings 24 in the peripheral area 20. The dummy openings 24 shown in
The arrangement of the dummy openings 24 follows the regularity of the arrangement of the stationary openings 22. In other words, assuming that stationary openings 22 are disposed also in the peripheral area 20 with the regularity of the plurality of stationary openings 22, the dummy openings 24 are formed at the positions coinciding with the stationary openings 22. The edge of the dummy opening 24 includes the edge 26 (see
As shown in
The first substrate 10 and the second substrate 28 are fixed to each other with a space formed by a seal member not shown. The space (the space sealed by the seal member not shown) between the first substrate 10 and the second substrate 28 is filled with oil 38 (e.g., a silicone oil).
The shutter 40 is supported by first springs 46, and is arranged to be lifted from the second substrate 28 as shown in
The first spring 46 is formed of an elastically deformable material. The first spring 46 has a plate-like shape with a small thickness, and is disposed so that the thickness direction is aligned in the lateral direction (a direction parallel to the surface of the second substrate 28), and the width direction is aligned in the vertical direction (a direction perpendicular to the surface of the second substrate 28). Thus, the first spring 46 is arranged to be able to deform in the lateral direction, namely the thickness direction thereof.
The first spring 46 has a first section 50 extending in a direction (a direction intersecting with (e.g., perpendicular to) the length direction of the driven opening 42) of getting away from the shutter 40, a second section 52 extending in a direction along the length direction of the driven opening 42 from the center of the driven opening 42 in the length direction toward the outside, and a third section 54 extending in a direction (a direction intersecting with (e.g., perpendicular to) the length direction of the driven opening 42) of further getting away from the shutter 40. Further, as indicated with the arrow in
The second substrate 28 is provided with second springs 58 each supported by a second anchor section 56. The second spring 58 is also formed of an elastically deformable material. The second spring 58 has a plate-like shape with a small thickness, and is disposed so that the thickness direction is aligned in the lateral direction (a direction parallel to the surface of the second substrate 28), and the width direction is aligned in the vertical direction (a direction perpendicular to the surface of the second substrate 28). Thus, the second spring 58 is arranged to be able to deform in the lateral direction, namely the thickness direction thereof. Further, the second spring 58 has a looped form, and is arranged so that a band-like portion extending from the second anchor section 56 is bent, and folded to return to the same second anchor section 56.
The second spring 58 is arranged to be opposed to the second section 52 of the first spring 46 on the side further from the shutter 40 than the second section 52. It is arranged that by applying a voltage to the second anchor section 56, the second section 52 is attracted by the second spring 58 due to the electrostatic attractive force caused by the potential difference from the second section 52 of the first spring 46. If the second section 52 is attracted, the shutter 40 is also attracted via the first section 50 integrated with the second section 52. In other words, the first spring 46 and the second spring 58 are for constituting a drive section 60 for mechanically driving the shutter 40. The drive section 60 is formed of the same material as the material of at least a part of the shutter 40.
It should be noted that as shown in
The shutter 40 has at least one driven opening 42. The driven opening 42 has a shape elongated in one direction, but is divided into a plurality of parts because bridges 62 and the recessed sections 44 for preventing the deformation of the shutter 40 and the shapes of the openings are provided. In this case, two or more driven openings 42 are arranged perpendicular to the length direction in each of the shutters 40. The driven openings 42 adjacent to each other are arranged to be parallel to each other.
As shown in
The shutter 40 moves between a first position P1 and a second position P2 due to the drive section 60. Each of the plurality of driven openings 42 is formed so as to extend in a direction intersecting with the direction between the first position P1 and the second position P2.
When the driven opening 42 of the shutter 40 and the stationary opening 22 of the light-blocking film 12 are communicated with each other, the light passes therethrough. The shutters 40 in the display area 18 each make the driven openings 42 and the stationary openings 22 be communicated with each other at the first position P1 to thereby transmit the light. If the stationary openings 22 of the light-blocking film 12 are closed due to the movement of the shutter 40, the light is blocked. The shutters 40 in the display area 18 are each disposed so that the driven opening 42 and the stationary opening 22 are shifted from each other to thereby block the light at the second position P2. In this case, the stationary openings 22 are displaced from the driven openings 24 in the direction (the moving direction of the shutter 40) between the first position P1 and the second position P2. The amount of the displacement is important for blocking the light.
The shutters 40 are each mechanically driven to thereby control transmission and blocking of the light to the stationary openings 22 of the light-blocking film 12. It is arranged that each pixel is constituted by the driven openings 42 and the stationary openings 22 corresponding to one shutter 40, and the image is displayed by a number of pixels. Therefore, there are disposed a plurality of (a number of) shutters 40. The shutters 40 and the drive sections 60 are arranged in the display area 18 for displaying an image using presence or absence, and an intensity level of the light transmitted through the driven openings 42 and the stationary openings 22.
As shown in
The edge 26 of the dummy opening 24 can visually be recognized on the substrate of the second shutter 68 due to the difference in reflectance or the difference in color between the light-blocking film 12 and the second shutter 68. Further, in this case, a part of the edge of the driven opening 42 of the second shutter 68 is exposed from the light-blocking film 12.
In the case in which the second shutter 68 is located at the second position P2, the edge 26 of the dummy opening 24 is located at a position shifted in the direction (the driving direction of the shutter 40) between the first position P1 and the second position P2 from the edge of the driven opening 42. The shift amount thereof corresponds to the shift amount of the stationary opening 22 and the driven opening 42 when arranging the virtual stationary openings 22 so as to match the dummy openings 24. It should be noted that the edge 26 of the dummy opening 24 extends in a direction perpendicular to the moving direction of the shutter 40.
As is understood from
According to the present embodiment, since the light is blocked if the shutter 40 is located at the second position P2, it is not achievable to measure the shift amount between the driven opening 42 and the stationary opening 22 in the display area 18. However, by measuring the distance d between the edge 26 of the dummy opening 24 and the driven opening 42 in the peripheral area 20, the shift amount between the driven opening 42 and the stationary opening 22 in the display area 18 can be detected.
Further, in the display device according to the present embodiment, the light is transmitted through the peripheral area 20 as described above. Therefore, as shown in
Alternately, as a modified example, it is also possible to form an internal light-blocking plate 74 provided to the second substrate 28 so as not to be provided with the opening in the peripheral area 20 instead of providing the printed section to the cover substrate 72 as shown in
In
The edge of the dummy opening 124 includes the first edge 174. In the case in which a shutter 140 in the peripheral area is located at the second position P2, the first edge 174 is located at a position shifted in the direction (the driving direction of the shutter 140) between the first position P1 and the second position P2 from the edge of the driven opening 142. In contrast thereto, the direction in which the first edge extends is perpendicular to the driving direction of the shutter 140. Therefore, by measuring the distance d1 (the distance in the driving direction of the shutter 140) between the first edge 174 of a dummy opening 124 and the driven opening 142 (in detail, the nearest edge thereof to the first edge 174), the shift amount between the driven opening 142 and the stationary opening can be detected in the display area having the correlative relationship. The small shift amount shows the fact that the sufficient light blocking is not assured.
The edge of the dummy opening 124 includes the second edge 176. The second edge 176 is located at a position shifted in the extending direction of the driven opening 142 from the edge of the driven opening 142 if the shutter 140 in the peripheral area is located at the second position P2. In other words, the second edge 176 extends in the driving direction of the shutter 140. Therefore, by measuring the distance d2 (the distance in the length direction of driven opening 142) between the second edge 176 of the dummy opening 124 and the driven opening 142 (in detail, the nearest edge thereof to the second edge 176), the shift amount of the shutter 140 in this direction can be detected.
While there have been described what are at present considered to be certain embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention.
Number | Date | Country | Kind |
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2011-229641 | Oct 2011 | JP | national |