AUTOSTEREOSCOPIC DISPLAY AND MANUFACTURING THEREOF
FIELD OF THE INVENTION
The invention relates to an autostereoscopic display comprising a display panel for displaying display data using an array of pixels, and an optical panel comprising an array of optical elements for directing light emitted by respective groups of the array of pixels in mutually different directions to enable stereoscopic viewing of the display data. The invention further relates to a method for manufacturing the autostereoscopic display.
BACKGROUND ART
3D displays are increasingly popular as they provide a viewer with stereoscopic perception of depth. So-termed autostereoscopic displays provide said stereoscopic depth perception without a need for the viewer to wear polarized or shutter-based glasses. For that purpose, autostereoscopic displays comprise, in addition to a display panel for displaying display data using an array of pixels, an optical panel which is provided in front of the display panel and which comprises an array of optical elements for directing light emitted by respective groups of the array of pixels in mutually different directions to enable stereoscopic viewing of the display data. Known examples of such optical panels are parallax barriers and lenticular lens arrays. Examples of autostereoscopic displays using the latter type are described in a paper by C. van Berkel et al entitled "Multiview 3D - LCD" published in SPIE Proceedings Vol. 2653, 1996, pages 32 to 39 and in GB-A-2196166.
In view of the need for the optical elements to be accurately aligned with the pixels of the display panel, the optical panel is typically mounted to a permanent manner in the autostereoscopic display, and in particular in such a manner that the position of the optical elements is fixed in relation to the array of pixels. However, such mounting of the optical panel may pose problems. A reason for this is that the optical panel is typically relatively thick and heavy compared to the display panel.
WO 2007/096818 discloses mounting a lenticular array in an autostereoscopic display. The lenticular array is mounted to a display panel which is mounted to a backlight unit. To secure the mounting of the lenticular array, a lateral securing member is disposed directly between the backlight unit and the edge of the lenticular array to prevent relative movement between the backlight unit and the lenticular array in a direction parallel to the plane of the display panel. The lateral securing member is fixed to the backlight unit by screw means. It is said that the screw means may also serve to secure the bezel of the autostereoscopic display to the backlight unit. SUMMARY OF THE INVENTION
A drawback of the lateral securing member of WO 2007/096818 is that it is insufficiently suitable for mounting optical panels which are relatively heavy, e.g., compared to the display panel.
One of the objects of the invention is to provide a mounting of an optical panel in an autostereoscopic display which is more suitable for optical panels that are relatively heavy.
A first aspect of the invention provides an autostereoscopic display comprising:
a display panel for displaying display data using an array of pixels;
an optical panel positioned parallel to the display panel, the optical panel comprising an array of optical elements for directing light emitted by respective groups of the array of pixels in mutually different directions to enable stereoscopic viewing of the display data;
- a support frame defining a framed opening for holding the optical panel in place along a periphery of the optical panel, the optical panel being inserted in the framed opening, and the framed opening being larger than the optical panel in at least one dimension, thereby forming at least one gap (DT) between the support frame and the optical panel; and
a spacing member inserted into the gap for establishing a structural connection between the optical panel and the support frame by bridging a width of the gap.
A further aspect of the invention provides a method for manufacturing an autostereoscopic display, the autostereoscopic display comprising a display panel for displaying display data using an array of pixels, the method comprising:
providing an optical panel for being positioned parallel to the display panel, the optical panel comprising an array of optical elements for directing light emitted by respective groups of the array of pixels in mutually different directions to enable stereoscopic viewing of the display data;
providing a support frame defining a framed opening for holding the optical panel in place along a periphery of the optical panel, the framed opening being larger than the optical panel in at least one dimension;
inserting the optical panel into the framed opening, thereby forming at least one gap between the support frame and the optical panel; and
inserting a spacing member into the gap for establishing a structural connection between the optical panel and the support frame by bridging a width of the gap.
The above measures provide an optical panel which serves to direct the light emitted by the display panel in different directions, thereby enabling stereoscopic viewing of display data displayed on the display panel. Such optical panels are known per se from the field of autostereoscopic displays, and include lenticular lens arrays and parallax barriers. The optical panel typically has a width, height and aspect ratio which are similar to that of the display panel, with deviations in width and/or height being typically minor and intended for manufacturability reasons. The optical panel is to be mounted in the autostereoscopic display. For that purpose, the autostereoscopic display is provided with a frame for holding the optical panel, i.e., a support frame. The support frame provides a framed opening for surrounding the optical panel from its sides, i.e. peripherally. The support frame may be known per se from the field of autostereoscopic displays, e.g., a bezel of the autostereoscopic display. It is noted that the support frame may be an integral part, and in particular a load-bearing structural part, of the autostereoscopic display.
The framed opening is larger than the optical panel in at least one dimension, e.g., horizontally or vertically. Accordingly, when surrounding the optical panel, there exists at least one gap between the support frame and the optical panel along said dimension. Due to the gap, the support frame does not hold the optical panel in place in a direction along the width of the gap. Hence, the optical panel may move in the direction of the gap when it is subjected to a sufficiently
large force. To prevent such movement, a spacing member is inserted into the gap which bridges the width of the gap, thereby establishing a structural connection between the optical panel and the support frame. The spacing member is thus dimensioned, or capable of assuming a dimension, which is substantially equal to the width of the gap. Here, the width of the gap refers to, when viewing the autostereoscopic display head-on, the dimension of the gap which is substantially perpendicular to that of the elongated length of the gap, i.e., the shorter of the two visible dimensions of the gap.
The inventors have recognized that mounting the optical panel to the display panel, and in particular to its backlight unit, is disadvantageous in case the optical panel is relatively heavy compared to the display panel since this puts considerable stress on the display panel. For example, in a 42" autostereoscopic display, the display panel including its backlight unit may weigh 3.4kg whereas the optical panel may weigh 10kg. Even if the difference in weight is less, the display panel remains a relatively fragile part of the autostereoscopic display. By providing a support frame which surrounds the optical panel, a structure is established which is capable of holding the optical panel in place from the sides of the optical panel. By providing a spacing member for bridging a width of a gap between the support frame and the optical panel, and by inserting the spacing member into the gap, a structural connection is established between the support frame and the optical panel. Accordingly, the optical panel is held in place by the support frame via the spacing member. Advantageously, stress exerted by the optical panel when the optical panel is subjected to a force such as gravity is transferred the support frame, thereby avoiding or reducing stress on the more fragile display panel. Another advantage is that the spacing member can be positioned freely along a length of the gap, thereby providing greater flexibility in mounting than the lateral securing member of WO 2007/096818 which is limited to a position where a screw hole is provided in the backlight unit of the display panel.
Optionally, the spacing member is formed by a pair of wedges which are arranged for, after being inserted into the gap, mutually engaging to establish the structural connection that bridges the width of the gap. A wedge is a tapered shape having a triangular cross section. Wedges are known to be used to fill gaps or spaces between objects. Another term for such wedges is wedge shims. This aspect of the present invention uses a pair of wedges which mutually engage in that they mechanically interact to form an engaging structure. The engaging structure is dimensioned such that it bridges the width of the gap, thereby providing the structural connection between the optical panel and the support frame. The inventors have recognized that a pair of wedges are well suited as spacing member. A reason for this is that a pair of wedges may be used to form an engaging structure which is adjustable in height, thereby allowing the pair of wedges to be used to bridge gaps of various widths. In particular, a pair of wedges may be used to form a stacked structure with two parallel sides, with a distance between the two parallel sides being variable depending on a manner of stacking the pair of wedges. Advantageously, a given pair of wedges may be used to bridge gaps of varying dimensions. The inventors have further recognized that, compared to the lateral securing member of WO 2007/096818, the pair of wedges provides a better structural connection in that the lateral securing member is affixed via a screw to the backlight, thereby providing a point-shaped structural connection which unevenly distributes stress to the backlight. The pair of wedges, however, provide an elongated structural connection between the optical panel and the support frame which more evenly distributes stress exerted by the optical panel to the support frame.
Optionally, each of the pair of wedges comprises a sloping side having a textured surface for engaging with the sloping side of the other one of the pair of wedges, and the pair of wedges are inserted into the gap with said sloping sides facing each other to establish the structural connection. Here, the term textured surface refers to the surface comprising vertical deviations on at least part of its surface. A textured surface provides enables the pair of wedges to better engage with each other, namely by means of friction or interlocking occurring between the respective surfaces. Advantageously, it is avoided that the pair of wedges easily mutually disengage due to a force being exerted on the pair of wedges causing the individual wedges to slide away from each other. Advantageously, by the sloping sides facing each other, an engaging structure is formed which provides two parallel sides which may be pressed against the optical panel and the support frame, respectively. It is noted that, depending on the exact shape of the wedge, the sloping side is also referred to as hypotenuse. Advantageously, the pair of wedges can be firmly wedged into the gap, thereby ensuring a stable fit and as such a stable mounting of the optical panel.
Optionally, the textured surfaces of the pair of wedges are formed by respective serrated surfaces which mutually engage by interlocking with each other. A serrated surface further improves the engagement of the pair of wedges since enables the pair of wedges to mutually engage by interlocking with each other. Advantageously, a more stable mounting of the optical panel is provided.
Optionally, the pair of wedges comprises:
a first wedge which is attached to the support frame and/or the optical panel, thereby providing a wedge-shaped gap between the support frame and the optical panel; and
a second wedge which is inserted into the wedge-shaped gap to engage with the first wedge.
By first attaching a first wedge to the support frame and/or the optical panel, the second wedge can be easily inserted into the resulting wedge-shaped gap to establish an engaging structure which structurally connects the optical panel to the support frame. Accordingly, the autostereoscopic display is obtained by mounting the optical panel in a convenient manner to the support frame.
Optionally, the pair of wedges are made out of plastic or rubber. Plastics and rubbers are well suited for various reasons, including their flexibility. For example, each wedge may be made out of Acrylonitrile Butadiene Styrene (ABS) or another type of thermoplastic. In particular, the flexibility may enable the pair of wedges to be more firmly wedged into the gap, namely by slightly deforming to match the local shape of the gap between the optical panel and the support frame.
Optionally, each of the pair of wedges has a wedge dimension along the width of the gap which is substantially between 0.5 and 0.75 times the width of the gap. By stacking the pair of wedges with the sloping sides facing each other, an engaging structure is obtained having a height which at least bridges the width of the gap. Accordingly, the pair of wedges can be firmly wedged into the gap.
Optionally, the at least one dimension is a longitudinal dimension along a width of the autostereoscopic display or a transversal dimension along a height of the autostereoscopic display.
Optionally, the spacing member is constituted by a mechanically expandable structure which is arranged for, upon insertion into the gap, being expanded to bridge a width of the gap. The spacing member is thus comprised of a mechanism which allows the spacing member to expand in at least one direction. Advantageously, the spacing member can initially assume outer dimensions
which easily fit the gap, thereby enabling the spacing member to be easily inserted into the gap. After insertion, the spacing member can then be expanded to firmly wedge into the gap.
Optionally, the spacing member is of a screw anchor-type structure. Screw anchors are well known structures which expand upon insertion of a screw. The spacing member can be constructed in a similar manner, in that it expands upon insertion of a screw or similar structure.
Optionally, the spacing member is formed by a pair of wedges which are mutually engageable so as to establish the structural connection that bridges the width of the gap, and the inserting the spacing member in the method of manufacturing the autostereoscopic display comprises:
- inserting a first wedge of the pair of wedges into the gap to provide a wedge- shaped gap between the support frame and the optical panel; and
inserting a second wedge of the pair of wedges into the wedge-shaped gap to engage with the first wedge.
The above method of manufacturing the autostereoscopic display is convenient since each of the wedges can be easily individually inserted into the gap, with the engaging structure only being formed after said insertion into the gap so as to firmly wedge into the gap.
Optionally, the method of manufacturing the autostereoscopic display further comprises attaching the first wedge to the support frame and/or the optical panel prior to inserting the second wedge. By attaching the first wedge to the support frame and/or the optical panel, a more stable fit of the pair of wedges is obtained and as such a more stable mounting of the optical panel.
Optionally, in addition to the first mentioned gap, an opposite gap is formed between the support panel and the optical panel at an opposite side of the optical panel, and the autostereoscopic display comprises a further spacing member which is inserted into the opposite gap. The optical panel is thus held in place by the support frame via spacing members from two opposite sides. Advantageously, the optical panel can be easily centered with respect to the support frame.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter. In the drawings,
Fig. 1 shows an autostereoscopic display comprising a display panel, an optical panel and a support frame in the form of a bezel of the autostereoscopic display;
Fig. 2a shows a zoomed-in view of a corner of the autostereoscopic display;
Fig. 2b shows a cross-section of the zoomed-in view of the autostereoscopic display;
Fig. 3a shows a spacing member which is formed by a pair of wedges, with a first wedge having been inserted in a gap between the optical panel and the support frame, thereby forming a wedge-shaped gap, and a second wedge being inserted into the wedge-shaped gap;
Fig. 3b shows a result of the second wedge being inserted, namely the pair of wedges mutually engaging to form an engaging structure that bridges a width of the gap;
Fig. 4 shows a spacing member which is formed by a screw anchor-type structure;
Fig. 5 shows a close-up view of a wedge from the pair of wedges;
Figs. 6a-6c show different views of the corner of the autostereoscopic display after different pairs of wedges have been inserted in respective sides of the corner; and
Fig. 7 shows a method of manufacturing the autostereoscopic display.
It should be noted that items which have the same reference numbers in different Figures, have the same structural features and the same functions, or are the same signals. Where the function and/or structure of such an item has been explained, there is no necessity for repeated explanation thereof in the detailed description.
DETAILED DESCRIPTION OF EMBODIMENTS
Fig. 1 shows an autostereoscopic display 100 comprising a display panel 1 10, an optical panel 200 and a support frame 300 in the form of a bezel of the autostereoscopic display. The autostereoscopic display 100 is an electronic device that represents information in visual form. Fig. 1 shows the autostereoscopic display 100 from a typical viewing position, i.e., facing a light-emitting front of the display panel 1 10. The autostereoscopic display 100 is shown in an upright position. Accordingly, any references to relative orientations such as upper, bottom, left, right, etc, refer to orientations when viewing the autostereoscopic display 100 being positioned in the upright position. Fig. 1 shows the optical panel 200 being placed in front of the display panel 1 10, with only the outline of the display panel 1 10 being shown. A reason for the outline being visible is that, by way of example, the display panel 1 10 of Fig. 1 has a slightly larger diagonal than the optical panel 200.
The display panel 1 10 is arranged for displaying display data using an array of pixels, and the optical panel 200 comprises an array of optical elements for directing light emitted by respective groups of the array of pixels in mutually different directions to enable stereoscopic viewing of the display data. Each of the display panel 1 10 and the optical panel 200 may be of a known type. For example, the display panel 1 10 may be a backlit, sidelit or frontlit Liquid Crystal Display (LCD) panel, and the optical panel 200 may be a lenticular lens array made of glass or a translucent plastic.
The support frame 300 defines a framed opening for holding the optical panel 200 in place along a periphery of the optical panel, i.e., from one or more sides of the optical panel. The optical panel 200 is inserted into the framed opening in such a way that it is positioned substantially in a plane defined by the framed opening, i.e., coplanarly. As a result, the support frame 300 surrounds the optical panel 200 from its sides. The framed opening is larger than the optical panel 200 in at least one dimension. In the example of Fig. 1 , the support frame 300 defines a framed opening which is both taller and wider, i.e., has a greater height and width, than the optical panel. Accordingly, elongated gaps are formed on all four sides of the optical panel 200 in case, as is also shown in Fig. 1 , the optical pane 200 is centered in the framed opening of the support frame 300.
Fig. 2a shows a zoomed-in view of a corner of the autostereoscopic display 100, with said corner being indicated in Fig. 1 as a dashed square ZV. In addition, Fig. 2b shows a cross- section of the zoomed-in view of the autostereoscopic display along the line CS as indicated in Fig. 2a. It can be seen that there exists an upper gap DT above the optical panel 200, with the upper gap having a width indicated by a double-ended arrow. Moreover, a left-hand gap DL exists at a left side of the optical panel 200, with the left-hand gap having a width indicated by a double-ended arrow.
Figs. 3a, 3b and 4 illustrate a spacing member being inserted into the upper gap in the earlier mentioned corner of the autostereoscopic display 100. It is noted, however, that the spacing member, or further spacing members, may also be inserted in gaps at other sides of the optical panel 200, e.g., in the left-hand, right-hand or bottom gap, or at a different position along the upper gap.
Fig. 3a shows a spacing member being inserted into the upper gap DT to establish a structural connection between the optical panel 200 and the support frame 300 by bridging the width of the gap DT. The spacing is formed by a pair of wedges 400, 410 which, after being inserted into the gap DT, mutually engage to form a structural connection 600 that bridges the width of the gap. Each of the wedges 400, 410 is constituted by a wedge shim which has a cross-section of a right triangle. It will be appreciated, however, that each of the wedges may also take another triangular form provided that the cross-section provides a tapered form so as to establish the wedge shape. In the example of Fig. 3a, each of the pair of wedges 400, 410 comprises a sloping side having a surface 402, 412 for engaging with the sloping side of the other one of the pair of wedges. Due to the wedges having a cross-section of a right triangle, said sloping side is also referred to as a hypotenuse. Fig. 3a shows a result of a first wedge 400 of the pair of wedges already being inserted into the gap DT, thereby providing a substantially wedge-shaped gap between the support frame 300 and the optical panel 200. Fig. 3a further shows, by means of an arrow 500, a second wedge 410 of the pair of wedges being inserted into the wedge-shaped gap to engage with the first wedge 400.
Fig. 3b shows a result of the second wedge 410 being inserted, namely the pair of wedges 400, 410 mutually engaging to form an engaging structure. The engaging structure establishes the structural connection 600 that bridges a width of the gap DT between the optical panel 200 and the support frame 300. It can be seen that the engaging structure can assume a variable height by the pair of wedges 400, 410 being differently positionable with respect to each other along their sloping sides. As a result, the engaging structure can assume a height which can bridge a gap having a width that is greater than a height of the individual wedges of said pair of wedges 400, 410.
To prevent the pair of wedges 400, 410 from disengaging due to pressure being exerted on the pair of wedges, each of the sloping sides may have a textured surface 402, 412. The textured surfaces 402, 412 may be arranged for providing an amount of surface friction which is sufficient for enabling the pair of wedges 400, 410 to firmly engage with each other, e.g., by having a suitable magnitude and/or frequency of the vertical deviations along the respective surfaces. Although not shown in Figs. 3a and 3b but rather in reference to Fig. 5, the textured surfaces 402, 412 may in particular be formed by respective serrated surfaces which mutually engage by interlocking with each other. Accordingly, the vertical deviations may be saw-like shaped to provide a firm engagement between each of the sloping sides of the pair of wedges by means of said interlocking.
Fig. 4 shows a spacing member 440 which is arranged to be expandable for, upon insertion into the gap DT, expanding to bridge a width of the gap. The spacing member 440 of Fig. 4 constitutes an alternative to the pair of wedges 400, 410 shown in Figs. 3a and 3b. In the example of Fig. 4, the spacing member 440 is shown to be a screw anchor-type structure which is arranged for expanding if a screw 442 is screwed 510 into the spacing member 440. The expansion of the spacing member 440 is indicated in Fig. 4 by means of arrows 520, with the expansion being in a direction which increases its outer dimensions so as to bridge the width of the gap DT. Accordingly, the
spacing member 440 can be firmly wedged into the gap DT. It will be appreciated that the spacing member may take yet another form which is capable of bridging the width of the gap. For example, the spacing member may be constituted by a rubber structure which can be wedged into the gap DT. In particular, the spacing member may have an outer dimension which slightly exceeds the width of the gap DT, with the spacing member being made of a compressible material which in turn enables the spacing member to be wedged into the gap by suitably compressing the spacing member.
Fig. 5 shows a close-up view of a wedge 400 from the pair of wedges. It can be seen that the wedge 400 has a flat, tapered shape and a sloping side having a serrated surface 402 for interlocking with the serrated surface of the other wedge 410 from the pair of wedges (not shown in Fig. 5). In the example of Fig. 5, the wedge 400 is shown to have a length DX of 15mm, a height DY of 6mm, and a thickness DZ1 , DZ2 decreasing from 2.7mm to 0.3mm to provide the tapered shape. It is noted, however, that the pair of wedges may also be differently dimensioned, namely such that the pair of wedges fit a particular gap between the optical panel and the support frame. The wedge 400 may be made of a thermoplastic such as ABS or any another suitable material. For example, the wedge 400 may be made out of rubber, wood, metal, another type of plastic, etc.
Figs. 6a-6c show different views of the corner of the autostereoscopic display 100 after two pairs of wedges have been inserted in respective sides of the corner. In particular, Figs. 6a-6c show a first pair of wedges 400, 410 being inserted into one side of the corner, i.e., the upper gap DT, and a second pair of wedges 420, 430 being inserted into another side of the corner, i.e., in the left- hand gap DL. It will be appreciated that the optical panel 200 may be completely and firmly secured with respect to the support frame 300 by using two pairs of wedges in each of four corners of the autostereoscopic display 100. Accordingly, by using eight pairs of wedges in total, a secure mounting of the optical panel 200 may be obtained. However, this is not a limitation, in that fewer or more securing members may be used, which in turn may also be inserted at other positions than the aforementioned corners of the autostereoscopic display 100. For example, a securing member may be inserted halfway along the length of each of the gaps, thereby enabling the optical panel 200 to be mounted with four securing members. Another example is that a first securing member may be inserted at 1/3 of the length of each of the gaps and a second securing member at 2/3 of said length.
To enable a convenient mounting of the optical panel 200, the pair of wedges 400, 410 may be sequentially inserted into the gap DT. For example, when referring to the first pair of wedges 400, 410, its first wedge 400 may be inserted into the gap DT, thereby providing a wedge-shaped gap between the support frame 300 and the optical panel 200. The second wedge 410 may then be inserted into the wedge-shaped gap during assembly of the autostereoscopic display 100 to engage with the first wedge 400. To further facilitate the mounting, the first wedge 400 may be attached to the support frame 300 and/or the optical panel 200, thereby preventing the first wedge 400 from sliding when inserting the second wedge 410 into the wedge-shaped gap. For example, a restraining member 310 may be provided which keeps the first wedge 400 in place along the direction of insertion of the second wedge 410, thereby preventing the first wedge 400 from sliding away. The restraining member 310 may be provided by a hook-like structure attached to, or part of the support frame 300. Alternative forms of attaching are equally possible. For example, the first wedge 400 may be glued, stapled or otherwise affixed to the support frame 300 and/or the optical panel 200.
Fig. 7 shows a method 700 of manufacturing an autostereoscopic display. Here, the term manufacturing refers to steps such as assembly and mounting. The method 700 may be used to manufacture the autostereoscopic display 100 of Figs. 1-6c. However, this is not a limitation, in that the method 700 may also be used to manufacture a different type of autostereoscopic display, e.g., having wider or narrower gaps between the support frame and optical panel, having a different type of support frame, etc. The autostereoscopic display comprises a display panel for displaying display data using an array of pixels. The method 700 comprises, in a step titled "PROVIDING OPTICAL PANEL", providing 710 an optical panel for being positioned parallel to the display panel, the optical panel comprising an array of optical elements for directing light emitted by respective groups of the array of pixels in mutually different directions to enable stereoscopic viewing of the display data. The method 700 further comprises, in a step titled "PROVIDING SUPPORT FRAME", providing 720 a support frame defining a framed opening for holding the optical panel in place along a periphery of the optical panel, the framed opening being larger than the optical panel in at least one dimension. The method 700 further comprises, in a step titled "INSERTING OPTICAL PANEL", inserting 730 the optical panel into the framed opening, thereby forming at least one gap between the support frame and the optical panel. The method 700 further comprises, in a step titled "INSERTING SPACING MEMBER", inserting 740 a spacing member into the gap for establishing a structural connection between the optical panel and the support frame by bridging a width of the gap. It will be appreciated that the steps of providing 710 the optical panel and providing 720 the support frame may be performed in any suitable order, e.g., simultaneously or in an order opposite to that of Fig. 7.
In the method 700, the spacing member may be formed by a pair of wedges which are mutually engageable so as to establish the structural connection that bridges a width of the gap. In this case, the step of inserting 740 the spacing member may comprise, as a first sub-step titled "INSERTING FIRST WEDGE", inserting 742 a first wedge of the pair of wedges into the gap to provide a wedge-shaped gap between the support frame and the optical panel. The step of inserting 740 may further comprise, as a second sub-step titled "INSERTING SECOND WEDGE", inserting 744 a second wedge of the pair of wedges into the wedge-shaped gap to engage with the first wedge.
The method 700 may further comprise an intermediary step titled "ATTACHING THE FIRST WEDGE", which comprises attaching the first wedge to the support frame and/or the optical panel prior to inserting the second wedge. For example, the first wedge may be attached to the support frame using the restraining member 310 as shown earlier in Figs. 6a-6c.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments.
In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually
different dependent claims does not indicate that a combination of these measures cannot be used to advantage.