JP5366806B2 - Autostereoscopic display device and method for manufacturing the same - Google Patents

Description

The present invention relates to an autostereoscopic display device of the type having a display panel having an array of display pixels for display on a display and an imaging device for directing different views to different spatial positions.

A first embodiment of an imaging device for use with this type of display is a barrier comprising a slit that is sized and positioned relative to the pixels underlying the display, for example. If the observer's head is in place, the observer can perceive a 3D image. The barrier is positioned in front of the display panel and is designed so that light from odd and even pixel columns is directed to the left and right eyes of the viewer.

  A disadvantage of this type of two-view display design is that the observer must be in a fixed position and can move only about 3 cm to the left or right. In a more preferred embodiment, there are several subpixel columns under each slit, rather than two. In this way, the observer can move from side to side and always perceive a stereoscopic image with his eyes.

The barrier device is easy to manufacture, but the light efficiency is not good. A preferred alternative is therefore to use the lens device as an imaging device. For example, an array of elongated lens elements extends parallel to each other and is provided overlying a display pixel array, the display pixels being viewed through these lens elements.

  The lens elements are supplied as sheets comprising these elements, each of which has an elongated semi-crystalline lens element. The lens elements extend in the column direction of the display panel, and each lens element lies on a respective set of two or more adjacent columns of display pixels.

  For example, in an apparatus where each lens is associated with two columns of display pixels, the display pixels in each column provide a vertical slice of the respective two-dimensional sub-image. The lens sheet directs corresponding slices from these two slices and display pixel columns associated with the other lenses to the left and right eyes of the user positioned in front of the sheet, so that the user can Observe. Thereby, the sheet of the lens element has a light output guiding function.

  In other devices, each lens is associated with a set of four or more adjacent display pixels in the row direction. Corresponding columns of display pixels in each set are appropriately arranged to provide a vertical slice from each two-dimensional sub-image. As the user's head moves from left to right, a series of consecutive different stereoscopic views are perceived, for example, giving the impression of looking around.

  The device described above provides an effective three-dimensional display. However, it has been found that there is an inevitable sacrifice in terms of the horizontal resolution of the device in order to provide a stereoscopic view. This sacrifice in resolution is unacceptable for certain applications, such as the display of small text characters for viewing from close range. For this reason, it has been proposed to provide a display device capable of switching between a two-dimensional mode and a three-dimensional (solid) mode.

  One way to do this is to provide an electrically switchable lens array. In the two-dimensional mode, the lens elements of the switchable device operate in a “path through mode”, i.e. they act in the same way as a planar sheet of light transmissive material. The resulting display is a high resolution equal to the inherent resolution of the display panel, which is suitable for displaying small text characters from a short viewing distance. In addition to the two-dimensional display mode, a stereoscopic image cannot be provided.

  In the three-dimensional mode, the lens element of the switchable device provides a light output guiding function as described above. The resulting display can provide a stereoscopic image, but has the inevitable resolution loss described above.

  In order to provide a switchable display mode, the lens element of the switchable device is formed from an electro-optic material such as a liquid crystal material having a refractive index that is switchable between two values. The device can then be switched between the modes by applying an appropriate potential to the flat electrodes provided above and below the lens element. The potential changes the refractive index of the lens element relative to the refractive index of the adjacent light transmissive layer. A more detailed description of the structure and operation of the switchable device can be found in US Pat. No. US 6,069,650.

  The present invention generally relates to mounting the lens device (which is either stereotactic or switchable) to a display panel. These lens devices must be mounted in close proximity to the underlying 2D display used. This is a prerequisite for the operation of the device, which requires the focus of the lens on the lens plate to be a (controlled) distance from the color filter of the 2D panel. Moreover, this distance must be kept constant across the active area of the display to ensure the same performance across the display output.

  The invention is defined by the independent claims. The dependent claims define advantageous embodiments.

  According to the present invention, an autostereoscopic display device according to claim 1 is provided.

The channel allows a defined volume size to increase while maintaining a slight spacing between the display panel and the imaging device. This increased volume, pressure in response to gas leaks beyond the sealing line is meant that no change so rapidly.

The spacing between the contact surface of the display panel and the imaging device is preferably less than 200 μm, more preferably less than 100 μm. The maximum space between the display panel and the imaging device is preferably at the seal line, and the reduced pressure creates a smaller spacing across the rest of the display.

  The groove preferably extends at least partially around the periphery of the display within the seal line. This means that it is not necessary to increase the length of the seal line substantially, and it is not necessary to increase the area of the display panel.

The groove preferably has a larger width and depth than the largest space between the contact surface of the display panel and the imaging device, so the addition of the volume of the groove is mainstream. The volume of the groove is greater than twice the remaining defined volume, and even more than five times.

  For example, the width of the groove can be in the range of 0.5 to 10 mm, and the depth of the groove can be in the range of 0.2 to 2 mm.

  The display panel may have an array of individually addressable radioactive, transmissive, refractive or diffractive display pixels, such as a liquid crystal display panel.

  The present invention also provides a method of manufacturing an autostereoscopic display device.

This method uses a vacuum to reduce the size of the gap prior to seal curing. The spacing between the contact surface of the display panel and the imaging device can be reduced below 200 μm, or more preferably below 100 μm. The seal may be cured before or after closing the inlet.

  The method further comprises defining a groove in the lens array that extends at least partially around the periphery of the display within the seal line. This provides the advantages described above.

1 is a schematic perspective view of a known autostereoscopic display device. The figure used for demonstrating the operation | movement principle of the lens array of the display apparatus shown by FIG. The figure used for demonstrating the operation | movement principle of the lens array of the display apparatus shown by FIG. Fig. 6 schematically illustrates how the lens apparatus provides different views (i.e. output from different sets of pixels) at different spatial locations. 1 shows a known 2D display that is the starting point for manufacturing a 3D display. The attachment method of this invention is shown. 2 shows a method of attaching a lens array according to the present invention to a display panel. FIG. 8 is a diagram used to explain a change to the device shown in FIG. 7.

In one aspect, the present invention provides a vacuum in which the lens array is attached to the display panel, a groove arrangement is used to increase the volume of the vacuum chamber, and the attachment is subject to gas leakage over time. Provided is an autostereoscopic display that is made small while maintaining a small gap between the lens array and the display panel.
In another aspect, the present invention provides a vacuum attachment method.

  FIG. 1 is a schematic perspective view of a known direct-view type autostereoscopic display device 1. This known device 1 has an active matrix type liquid crystal display panel 3 which acts as a spatial light modulator for displaying on the display.

  The display panel 3 has an orthogonal array of display pixels 5 arranged in rows and columns. Only a few display panels 5 are shown in the figure for the sake of clarity. In practice, the display panel 3 may have about one thousand rows and thousands of columns of display pixels 5.

  The structure of the liquid crystal display panel 3 is quite normal. In particular, the panel 3 has a pair of spaced-apart transmissive glass substrates provided with a twisted nematic or other liquid crystal material oriented between the substrates. The substrate carries a pattern of transmissive ITO (indium tin oxide) electrodes on the contact surfaces of these substrates. A polarizing layer is further provided on the outer surface of the substrate.

  Each display pixel 5 has electrodes facing each other on the substrate, and a liquid crystal material is interposed between the electrodes. The shape and arrangement of the display pixel 5 are determined by the shape and arrangement of the electrodes. These display pixels 5 are regularly spaced from each other by a gap.

  Each display pixel 5 is associated with a switching element such as a TFT (thin film transistor) or TFD (thin film diode). The display pixel operates to display on the display by supplying an addressing signal for the switching element, and suitable addressing methods are known to those skilled in the art.

  The display panel 3 is illuminated by a light source 7 having a planar backlight that extends over the area of the display pixel array in this case. The light from the light source 7 is directed to the display panel 3, and the individual display pixels 5 are driven to modulate the light and display it on the display.

  The display device 1 further includes a lens sheet 9 that performs a view forming function and is arranged over the display surface of the display panel 3. This lens sheet 9 has a row of lens elements 11 extending parallel to each other and is shown in a dimension enlarged by one for clarity.

  The lens element 11 is in the form of a convex cylindrical lens, and these elements are for supplying different images, ie views, from the display panel 3 to the eyes of the user positioned in front of the display device 1. , Acts as light output guiding means.

  The autostereoscopic display device 1 shown in FIG. 1 can supply several separate perspective views in different directions. In particular, each lens element 11 lies on a small set of display pixels 5 in each row. The lens element 11 projects each set of display pixels 5 in different directions to form the several separate views. As the user's head moves from left to right, the user's eyes sequentially receive separate views of the several views.

  As described above, it has been proposed to provide an electrically switchable lens element. This allows the display to be switched between 2D and 3D modes.

  2 and 3 show an array of electrically switchable lens elements 35 that can be used in the apparatus shown in FIG. This array has a pair of transparent glass substrates 39 and 41, and transparent electrodes 43 and 45 formed of ITO are provided on the contact surfaces of these substrates. An inverted lens structure 47 formed using a replication technique is provided adjacent to the upper substrate 39 between the substrates 39 and 41. A liquid crystal material 49 is also provided adjacent to the lower substrate 41 between the substrates 39 and 41.

  2 and 3, the reverse lens structure 47 makes the liquid crystal material 49 into a parallel elongated lens shape between the reverse lens structure 47 and the lower substrate 41. As shown in FIG. The surface of the inverted lens structure 47 and the lower substrate 41 in contact with the liquid crystal material also includes an alignment layer (not shown) for aligning the liquid crystal material.

  FIG. 2 shows the array when no potential is applied to the electrodes 43 and 45. In this state, the refractive index of the liquid crystal material 49 is significantly higher than the refractive index of the inverse lens array 47, so that the lens shape provides a light output guiding function as will be explained.

  FIG. 3 shows an array when an AC potential of about 50 to 100 V is applied to the electrodes 43 and 45. In this state, since the refractive index of the liquid crystal material 49 is substantially the same as the refractive index of the reverse lens array 47, the lens-shaped light output guiding function is canceled as will be described. Thus, in this state, the array operates effectively in a “pass-through” mode.

  Further details of the structure and operation of an array of switchable lens elements suitable for use in the display device shown in FIG. 1 can be found in US Pat. No. 6,069,650.

FIG. 4 shows the operating principle of a lens-type imaging device as described above, and also shows a backlight 50, a display device 54 such as an LCD, and a lens array 58.

  The invention also relates to mounting a lenticular (or other) lens array device on the display panel.

  FIG. 5 shows the basic known design of the 2D module.

  The apparatus has an LC module 60 and a stack 62 consisting of a polarizer and brightness enhancement foil on a substrate 76.

  The LC module includes two glass substrates 64 on which two polarizers 68 are provided with an LC material layer 66 interposed therebetween. The seal is indicated at 70. This LC module generally has a thickness of about 2 mm.

  The display module has a base plate 72, a bezel 71 is used to provide mechanical stability in the 2D module, and a spacer block / damping element 74 defines the LC cell mounting location for the stack 62. The spacer 74 is about 2 mm thick and the resulting space between the LC panel and stack 62 interface is about 3.8 mm.

  The stack is typically about 0.9 mm thick.

  The backlight is not shown in FIG.

  One conventional method for manufacturing a 3D display is to start with a complete 2D display module and update it to a 3D display.

To assemble the structure shown in FIG. 5 using this technique, the following steps:
-Dismantling the 2D panel from the 2D module by removing the bezel 71 and removing the electronic device;
-Placing the 2D panel on a flat table;
Applying the lens array with an edge seal to produce a 3D panel;
Inserting an additional glass plate behind the 3D panel so that it is possible to squeeze the 3D panel between the lens array and the additional glass plate, and 3D into the original 2D module. Assembling the panel to produce a 3D module;
Execute.

Many problems solved by this manufacturing process,
-Electronic equipment may be damaged during assembly and disassembly of the display;
The manufacturing process is very time consuming and cumbersome,
The lens is simply attached to the panel at the edge, so the panel plate and lenticular lens are curved, making it very difficult to guarantee performance,
The display panel itself is not perfectly flat and has peaks and valleys that make it very difficult to guarantee performance, and the requirement for additional plates behind the 3D panel is the weight of the system And may change the thermal behavior of the system, leading to performance changes.
There's a problem.

  This method of disassembly and reassembly thus has a number of drawbacks.

  Although the present invention provides a vacuum mounting method that still allows standard 2D panels to be changed, thereby enabling the use of a shelf display module, it addresses some of the problems discussed above.

  FIG. 6 is a flowchart for explaining the assembly method of the present invention.

  The lens sheet is processed by cleaning 78 and a seal is applied to the surface of the sheet in step 79. This seal line includes the inlet and is around the edge of the lens sheet so as to surround the display area in the finished product. Alternatively, the seal may be attached to the display panel surface. The lens array is typically 2 to 5 mm thick.

  The 2D display module is processed in step 80 by removing the bezel 71 from the 2D module. However, it is not necessary to remove the two-panel display and thereby disconnect the display electronics.

  After cleaning in step 82, in step 84 the lens array is aligned with the seal line and in step 85 the two panels are bonded together.

  In step 86, a vacuum is applied to the space defined by the lens array, seal line and 2D panel.

  In step 88, the inlet is closed and in step 90 the seal is cured.

  This process allows the LCD panel and lens plate to be mounted together as closely as possible, which has as little gap as possible, comparable to the tolerance level for the LCD panel and lens plate. Using a seal line means that the plate cannot move after the process is finished. The seal line is preferably a curable fluid to form a gasket and the seal is used to bond the LCD panel and lens plate together.

  A vacuum is used to reduce the size of the air gap between the LCD and the lens plate. By exhausting the air in the gap, the volume of the gap is reduced.

  Preferably, the seal line is pressurized to a thickness of 50 to 100 μm. The application of vacuum ends when the distance between the LCD panel and the lens plate reaches the desired distance. This spacing is smaller at the center of the display area and is greatest for seal lines where the spacing increases to 50-100 μm.

  The seal line can be cured by water permeation, otherwise a two-component seal can be used, and a temperature and / or UV is used to effect curing.

  As a result, both plates are attached together very closely. The presence of a vacuum in the gap does not require the plate to remain fixed and is used as part of the alignment process rather than the fixing process.

  This method prevents damage to the electronics during assembly and disassembly because the display no longer requires complete disassembly. The lens array and the panel are intimately attached across the entire active area of the display due to the pressure difference inside and outside the lens-panel combination, thereby providing gap uniformity. This method prevents the need for additional glass plates.

  After inspecting the seal in step 92, the bezel 71 attached in step 96 is used again in step 94 to fit additional lens arrays.

  Finally, the protective plate is utilized in step 98 and the finished product is supplied to the set maker.

  FIG. 7 shows the assembled device of the present invention using the same reference numbers as FIG. The lens array is shown as 100, the seal line is shown as 102, and the modified bezel is shown as 71 '.

As described above, the volume to which the vacuum is applied is a very small volume. For example, the size of the gap across most areas of the display is in the range of 0 to 10 μm. For the area inside the 940 × 530 mm ² seal line, an average thickness of 1 μm gives a vacuum containing volume of 498 mm ³ .

  The vacuum creates a pressure difference on both sides of the seal line. For an imperfect seal, this serves as a driving force for nitrogen, oxygen and other gases to penetrate the vacuum region. As a result, the vacuum level decreases very slowly, depending on the permeability of the sealing material.

  Even if the attachment is mechanically secured by a seal line, this pressure change causes a slight change in the spacing over time, particularly an increase in the gap between the lens array and the panel plate.

  The modification described with reference to FIG. 8 allows the rate at which the vacuum level is reduced by the permeability to be significantly reduced. As a result, the rate at which the gap between the lens array and the display panel plate increases is significantly reduced. This contributes to an increase in the service life of the product.

  As shown in FIG. 8, the volume of the vacuum space 100 is increased by the groove array 112 without increasing the length of the seal line. These grooves constituting the vacuum buffer are conceivable.

Adjacent to the seal line defined by the seal 102, an additional buffer space is created that widens the vacuum containing region. For example, compared to the vacuum volume of 498 mm ³ described above, considering the groove width and depth to be 1 mm, the volume can be increased by 2940 mm ³ . This has increased about 7 times. As a result, the effect of permeable gas is significantly reduced.

  The above-described embodiment uses a liquid crystal display panel having a display pixel pitch in the range of 50 μm to 1000 μm, for example. However, it will be apparent to those skilled in the art that alternative types of display panels such as organic light emitting diodes (OLED) or cathode ray tube (CRT) displays are used.

  Since the manufacture and materials used to assemble the display and lens array are common and well known to those skilled in the art, these details are not described.

  Various other modifications will be apparent to those skilled in the art.

Claims (16)

A display panel with an array of display pixels for display on a display, arranged in rows and columns, and to direct the output from different pixels to different spatial locations to allow viewing of a stereoscopic image Imaging device,
In an autostereoscopic display device having:
The display panel and the imaging device are coupled together around a seal line, and a volume defined between the display panel, the imaging device and the seal line has a reduced pressure, and the display panel and At least one of the imaging devices includes a groove in the volume, and the groove has a volume larger than twice the remaining volume of the defined volume . The apparatus according to claim 1, wherein a distance between contact surfaces of the display panel and the imaging device is smaller than 200 μm. The apparatus according to claim 2, wherein the distance between the contact surface of the display panel and the imaging device is smaller than 100 μm. The apparatus according to claim 2 or 3, wherein a maximum distance between the display panel and the imaging device is a seal line.   5. A device according to any preceding claim, wherein a groove extends at least partially around the periphery of the display within the seal line. The apparatus according to claim 5, wherein the groove has a width and depth larger than the maximum distance between contact surfaces of the display panel and the imaging device.   7. The apparatus of claim 6, wherein the groove width is in the range of 0.5 to 10 mm and the groove depth is in the range of 0.2 to 2 mm.   8. A device according to any preceding claim, wherein the display panel comprises an array of individually, addressable radioactive, transmissive, refractive or diffractive display pixels.   The apparatus according to claim 1, wherein the display panel is a liquid crystal display panel. In a method of manufacturing an autostereoscopic display device,
-Removing the bezel from the display module to expose the display panel;
Providing an imaging device for directing the output from different pixels to different spatial positions in order to be able to inspect a stereoscopic image;
-Affixing a closed seal line including the inlet to the outer edge of the 2D panel or the outer edge of the imaging device;
Aligning the imaging device and the display panel with the seal line between them;
-Reducing the volume pressure defined between the imaging device, the seal line and the display panel, thereby reducing the gap between the contact surface of the display panel and the imaging device. step, and - closing the inlet, a method of have a step of curing the sealing, the method is provided with a groove in the display panel and the inside volume to at least one of the imaging device step And the groove has a volume greater than twice the remaining volume of the volume . The method of claim 10, wherein a spacing between contact surfaces of the display panel and the imaging device is reduced below 200 μm. The method of claim 11, wherein the spacing between the tangent surfaces of the display panel and the imaging device decreases below 100 μm. 12. The method according to claim 10 or 11, wherein a maximum distance between the display pixel and the imaging device is at the seal line.   14. A method according to any one of claims 10 to 13, further comprising defining a groove in the lens array that extends at least partially around a periphery of the display in the seal line. The method of claim 14, wherein the groove is defined to have a width and depth greater than the maximum spacing between the tangent surfaces of the display pixel and the imaging device.   The method of claim 15, wherein the groove width is defined to be in the range of 0.5 to 10 mm and the groove depth is defined to be in the range of 0.2 to 2 mm.

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