EP1529229A2

EP1529229A2 - Display device

Info

Publication number: EP1529229A2
Application number: EP03790718A
Authority: EP
Inventors: Edmund PÖTSCH
Original assignee: Fujitsu Technology Solutions GmbH
Current assignee: Fujitsu Technology Solutions Intellectual Property GmbH
Priority date: 2002-08-13
Filing date: 2003-08-13
Publication date: 2005-05-11
Also published as: WO2004021051A2; AU2003260271A1; AU2003260271A8; DE10237119B3; CN1646945B; WO2004021051A3; CN1646945A; US7388577B2; US20050259082A1

Abstract

The invention relates to a display device, comprising a display layer (2) and a touch-sensitive layer (3), running parallel to the above. Said display devices are characterised in that an anti-reflection grating is provided, arranged on the touch-sensitive layer (3), whereby the grating elements may be displaced relative to each other or have a touch-sensitivity, which is independent of other grating elements.

Description

description

display device

The invention relates to a display device with a display layer and a touch-sensitive layer running parallel thereto.

Such display devices are used when not only information is to be depicted graphically, but also input via the device. Such a display device is particularly useful when using graphical user interfaces of operating systems or application programs. In these cases, functions are activated by buttons, the buttons either being clickable with a cursor, for example using a mouse, or the corresponding function can be activated directly by touching the display device. Such display devices are often referred to as a touch screen.

Since an input device can be saved by such display devices, display devices of this type are preferably used for small portable devices, for example the so-called handhelds or PDAs. Especially in mobile operation, however, the problem arises that a relatively high ambient brightness is present and reflections occur on the display device which considerably impair the readability of the display device.

From tube display devices, in which the problem of reflection also occurs, it is known to arrange a grating in front of the screen to avoid reflections on the screen surface, this usually being a fine-meshed wire mesh, through which the information shown is still for a viewer good to see but oblique ambient light can no longer cause reflections.

Such a wire mesh or a similar device cannot be used with touch-sensitive display devices because, because of the relatively rigid structure, a broad printing area would result even when in contact with a relatively pointed object such as a pen, which can lead to incorrect entries. Even with a high resolution of the touch-sensitive layer, e is no longer possible in precise work.

Another known way of avoiding disturbing reflections is to roughen the surface pointing towards an observer, for example by etching. A disadvantage of this solution is that the scattering effect not only affects incident ambient light, but also the light that is emitted by individual pixels of the display layer is scattered, and the sharpness of the image is thus reduced.

The object of the invention is therefore to provide a display device which has a touch-sensitive layer and which nevertheless has protection against surface reflections from ambient light.

This object is achieved according to the invention by a display device of the type mentioned at the outset, which is characterized in that an anti-reflection grating comprising grating elements which can be moved relative to one another is provided on the side of the touch-sensitive layer facing away from the display layer. The object is also achieved by a display device of the type mentioned at the outset, which is characterized in that a grid-like surface structuring is provided on the surface of the touch-sensitive layer facing away from the display layer, the grid spacing being such that the pixel spacing of the display layer it is agreed that the ratio of the grid spacing to the pixel spacing is an even number.

The even ratio of the grid spacing to the pixel spacing ensures that the light emitted by pixels of the display layer is not scattered, but rather reaches the viewer directly. Quasi microscopic channels are formed through the grid. In contrast, obliquely incident light is reflected or absorbed by the grating elements.

The object is also achieved by a display device of the type mentioned, which is characterized in that the beruhrungsempfindliche layer includes grating elements, the grating pitch is matched to the pixel pitch of the display layer so ^'that the ratio of the grating pitch to dem'Pixelabstand is even.

In such an embodiment, the lattice elements that prevent reflections are already integrated in the touch-sensitive layer. A fourth solution to the problem consists in forming the touch-sensitive layer in a display device of the type mentioned at the beginning by means of stripe-shaped grid elements arranged in a grid and integrating touch sensors in the nodes of the grid. In such an embodiment, the touch-sensitive components and the reflection-preventing components are not separate units, but rather the same elements fulfill functions for avoiding reflection as well as for producing the touch sensitivity.

In a display device of the type mentioned at the outset, it is advantageous to design the grid elements in the form of strips, the grid elements being movable relative to one another at the nodes of the grid. The strip-like design ensures good anti-reflection behavior. It is particularly advantageous to provide the angle of the lattice elements adjustable in relation to the touch-sensitive layer. Due to the grating elements, the viewing direction parallel to the grating elements is strongly preferred over an oblique viewing angle. By changing the angle of the grating elements with respect to the touch-sensitive layer, the preferred viewing direction can be set according to the user's wishes.

A further advantageous embodiment of the first solution provides that the anti-reflective grille can be removed. In the third solution mentioned, in which the touch-sensitive layer contains lattice elements, it is advantageous that the lattice elements have liquid crystals. This means that the anti-reflective behavior can be switched off or on if necessary.

In the latter solution, it is advantageously provided to integrate electrical conductors running parallel to the display layer in the grid elements and to produce the grid elements from an elastic material, means being provided for evaluating capacitive, inductive or resistive characteristic values of two electrical conductors of different grid elements.

Further advantageous embodiments of the invention are specified in the subclaims.

The invention is explained in more detail below on the basis of exemplary embodiments. Show it:

FIG. 1 shows a PDA with a display device according to the invention,

FIG. 2 shows a schematic illustration of a first exemplary embodiment of a display device according to the invention, FIG. 3 shows a three-dimensional representation of grid elements of the exemplary embodiment from FIG. 2,

FIGS. 4 to 6 variants of the execution of grid elements,

FIG. 7 shows a further exemplary embodiment with the integration of the touch-sensitive properties in the lattice elements,

FIG. 8 shows a display device according to the invention with a removable anti-reflection grating,

Figure 9 shows the arrangement ^'of Figure 8 with removable anti-reflection grating,

Figure 10 shows a display device according to the invention with controllable grid elements.

FIG. 1 shows a PDA (Personal Digital Assistant) 11 with a display device 1 according to the invention. The display device 1 is designed to be touch-sensitive and, for this purpose, has a touch-sensitive layer 3. In the symbolic illustration in FIG. 1, an anti-reflection grating 4 is also provided, which is used for elimination disturbing reflections is suitable.

Figure 2 shows the display device of Figure 1 in a more detailed representation. As can be seen from FIG. 2, the antireflection grating 4 consists of a plurality of grating elements 5. These stand at a predetermined angle 9 on a touch-sensitive layer 3. The angle 9 is preferably 90 °. Microscope channels 10 are formed by the grating elements 5, through which a viewer looks at the touch-sensitive layer and the display layer 2 underneath. To ensure good visibility is achieved, the grid elements 5 are aligned parallel to the viewing direction 12. Ambient light 18 incident on the side is absorbed by the grating elements 5 and thus only reaches a small proportion of the at least partially reflecting surface of the touch-sensitive layer 3 or the display layer 2.

In particular in the case of small portable devices such as the PDAs shown in FIG. 1, it is easy to hold the device in such a way that the viewing direction is perpendicular to the display device 1. For larger devices such as laptops or fixed flat screens, it is not always possible or not always easy to figure the optimal orientation of the display device ^'1 to the user to bewerk-. It is therefore "advantageous if the grille elements 5 are not rigid, but are movable so that their angle 9 can be changed relative to the touch-sensitive layer 3. In an embodiment with an adjustable angle of the grille elements, an optimal alignment can take place by user setting or automatically in Depending on the incident ambient light, a sensor can be provided, for example, which measures the angle of incidence of ambient light and controls the grating elements 5 via appropriate control devices so that they are at an optimal angle.

The grid elements 5 are either partially transparent or not transparent. In order to achieve a satisfactory effect, the material of the grid elements 5 should be light-absorbing or should form a light-absorbing surface.

For the quality of the display device 1, it is necessary that the grid spacing between grid elements 5 is matched to the pixel spacing of the pixel elements 8 of the display layer 2. Otherwise, the so-called moire effect can occur. This occurs when grid elements 5 due to odd-numbered spacing relationships in certain areas lie above pixel elements 8, while in other areas the grid elements 5 lie exactly between two pixels. The moire effect can be avoided if the ratio of grid spacing to pixel spacing is even. In Figure 2, the grid spacing is chosen so that it is twice the pixel spacing. Therefore, there is a grid element 5 on two pixels 8.

FIG. 3 shows a three-dimensional schematic representation of the arrangement of the lattice elements 5. The lattice nodes 13 are each designed so that the lattice elements 5 are flexible with respect to one another by slots in the strip-shaped lattice elements 5. This is therefor important that ^'the grid elements 5 of this in each case on the underlying to ^""' is transmitted instead of the touch-sensitive layer 3 in printing ^'.

FIGS. 4 to 6 show alternative configurations of the anti-reflection grating ^" '4. In the representation in FIG. 4, knobs are provided at the grid node points 13. This knob-shaped configuration ensures very favorable power transmission to the touch-sensitive layer 3. With a corresponding size of the knobs and a correspondingly small lattice spacing can produce a sufficient anti-reflective effect.

In figure 5 also streifenfδrmige grating elements 5 are provided, these being completely interrupted at the nodes 13 ^'. The width of the strips 5 can be reduced further, so it is not necessary that the strips extend over the entire length between two nodes 13.

In the illustration in FIG. 6, bristle-like grating elements 7 are provided. Such a design of the grid elements is particularly suitable when the ratio of the grid spacing to the pixel spacing is significantly greater than 1. at In an embodiment of grid elements in which only the grid nodes 13 enable the detection of a touch, the resolution of the touch-sensitive layer 3 would be very low. However, since each bristle is able to transmit a force exerted on it from above, a good resolution of contacts can be achieved even with a large grid spacing.

In the embodiment of FIG. 7, the functions of the sensitive layer 3 and the anti-reflective grating 4 are combined with one another. This is achieved in that the lattice elements 15 are not only designed in the form of strips to develop an anti-reflective effect, but are also sensitive to touch. This is achieved in that electrical conductors 14 run in the grid elements 15, which, which cannot be seen in FIG. 7, do not touch in the nodes 13. By specifically evaluating individual electrical conductors 14, a change in the distance between two electrical conductors 14 in individual nodes 13 can be evaluated. A change means that capacitive, inductive or resistive values change. For this purpose, the grid elements 15 must be elastic so that the application of pressure also results in a change in the distance between two conductors.

Another possibility for combining the antireflection function and the touch sensor function is to use grating elements, such as are shown in FIG. 5, and to additionally set up touch sensors at the nodes. A capacitively sensitive sensor element, for example, which is arranged at a node 13, is sufficient for this. Capacitive sensor elements work in such a way that an object brought into the vicinity changes the electric field, which leads to a change in capacitance of an electrode which represents the sensor element. This change in capacity can now be evaluated. FIG. 8 shows the possibility of pivotably connecting the anti-reflection grating 4 to a housing which accommodates the touch-sensitive layer 3 and the display layer 2. In this way, the display device can also be used without an anti-reflection grating 4.

FIG. 9 shows a configuration similar to that of FIG. 8, but the reflection grating 4 is not pivotably arranged on the housing, but rather can be put on. Positioning pins 16 ensure that the anti-reflection grating is positioned in such a way that the grating elements do not interfere with the light emitted by pixel elements of the display layer 2.

FIG. 4 shows an embodiment of a display device according to the invention, in which 3 lattice structures are incorporated into the touch-sensitive layer. In this case, the grid elements need not be flexible. The grid elements 17 need not be flexible in this case. The lattice elements can also consist of liquid crystals or of electrochromic material. In this case, the grid elements can be switched on or off by applying an appropriate control voltage. In order not to hinder the representative properties of the display layer, the grid spacing should also be matched to the pixel spacing in this case.

If liquid-crystalline antireflection gratings are used, the optical alignment of the grating elements can be adjusted by applying a corresponding control voltage. The setting can be made either manually by the user or automatically depending on the strength and / or the angle of the ambient light. LIST OF REFERENCE NUMBERS

1 display device

2 display layer

3 touch sensitive layer

4 anti-reflective grids

5 grid element (strips) 6 grid element (knobs)

7 grid element (bristles)

8 pixels

9 angles

10 microscopic channel 11 PDA

12 viewing direction

13 grid nodes

14 electrical conductors

15 combi grid element 16 positioning pins

17 grid elements

Claims

claims

1. Display device with a display layer (2) and a parallel to it touch-sensitive layer (3), characterized in that an anti-reflection grating (4) is provided from mutually movable grating elements on the side of the anti-reflection layer (3) facing away from the display layer (2) is.

2. Display device according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the grid element (5) are formed strip-like, wherein the grid elements (5) at nodes (13) of the grid are mutually movable.

3. Display device according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the grid elements (7) are bristle-like.

4. Display device according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the grating elements (6) are nub-like.

5. Display device according to one of claims 1 to 4, that the grid spacing is matched to the pixel spacing of the display layer (2) such that the ratio of the grid spacing to the pixel spacing is an even number.

6. Display device according to one of claims 1 to 5, characterized in that the angle (9) of the grid elements (5, 6, 7) relative to the touch-sensitive layer (3) is adjustable.

7. Display device according to claim 6, d a d u r c h g e k e n n z e i c h n e t that

Means are provided for the automatic adjustment of the angle (9) depending on the angle of the incident ambient light (18).

8. Display device according to one of claims 1 to 7, that the grid elements (5; 6; 7) consist of a light-absorbing material.

9. Display device according to one of claims 1 to 8, d a d u r c h g e k e n n z e i c h n e t that the anti-reflective grille (4) is removable.

10. Display device with a display layer (2) and a touch-sensitive layer (3) running parallel thereto, characterized in that a grid-shaped surface structuring is provided on the surface of the touch-sensitive layer (3) facing away from the display layer (2), the grid spacing on the pixel spacing of the display layer (2) is matched such that the ratio of the grid spacing to the pixel spacing is even.

11. Display device with a display layer (2) and a parallel touch-sensitive layer (3), characterized in that the touch-sensitive layer (3) contains grid elements (17), the grid spacing being matched to the pixel spacing of the display layer (2) such that the ratio of the grid spacing to the pixel spacing is even.

12. Display device according to claim 11, d a d u r c h g e k e n n z e i c h n e t that the lattice elements (17) have liquid crystals.

13. Display device according to claim 11, that the grid elements (17) consist of an electrochromic material.

14. A display device according to claim 12 or 13, which also means that means are provided for automatically adjusting the optical properties of the grating elements (17) as a function of the ambient light conditions.

15. Display device with a display layer (2) and a parallel touch-sensitive layer (3), characterized in that the touch-sensitive layer (3) is formed by grid-shaped, strip-shaped grid elements (15) and in the nodes (13) of the grid touch sensors are integrated.

16. A display device according to claim 15, characterized in that the grid elements (15) parallel to the display layer (2), which do not touch in the nodes (13) of the grid include electrical conductors (14) and the grid elements (15) made of an elastic material exist, means being provided for evaluating the spacing of the conductors (14) at nodes (13) of the grid.

17. Display device according to claim 15, so that the touch sensors are capacitive sensor elements.