JP3755573B2 - Backlight built-in type liquid crystal display device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a backlight built-in liquid crystal display device integrated with a backlight by transferring a thin film device between a plurality of substrates, and a method for manufacturing the same.
[0002]
[Prior art]
A liquid crystal display device including a thin film transistor (TFT), which is a thin film device, as a drive circuit source, uses liquid crystal molecules (between the substrate and the counter substrate) that are sealed by a voltage controlled by the TFT formed on the substrate. The liquid crystal display element) has a configuration capable of displaying an image by controlling the optical rotatory power of the liquid crystal display element and controlling the translucency of each pixel.
[0003]
This liquid crystal display device is shown in FIG. As shown in FIG. 15, the active matrix substrate 220 on which thin film devices such as the active matrix 222 and / or the drive circuit 224 are formed, and the counter substrate 240 are seals formed along the outer peripheral edge of the counter substrate 240. A material (not shown) is pasted through a predetermined gap, and liquid crystal 230 is sealed in the gap.
[0004]
The pixel electrode formed in the active matrix 122 and the transparent counter electrode formed on the counter substrate 240 face each other with the liquid crystal 230 interposed therebetween, and liquid crystal molecules are driven by an electric field applied between the pixel electrode and the counter electrode. .
An alignment film is formed on the surface of the active matrix 222 that is in contact with the liquid crystal 230 and the surface of the counter substrate 240 that is in contact with the liquid crystal 230, and determines the alignment of liquid crystal molecules in an electric field-free state.
[0005]
The liquid crystal driving unit composed of the active matrix substrate 220, the liquid crystal 230, and the counter substrate 240 is further sandwiched between two polarizing plates 210 and 250 having different polarization directions. The polarization directions of the polarizing plates 210 and 250 are aligned with the alignment directions of the alignment films formed on the surfaces of the active matrix substrate 220 and the counter substrate 240, respectively.
[0006]
In order to enable color display, a color filter and / or a black matrix is formed on the counter substrate 240.
[0007]
As described above, since the liquid crystal display device has a structure in which a large number of substrates are bonded to each other, there is a drawback in that the thickness of the display device increases. In particular, as shown in FIG. 15, the backlight 200 required for the transmissive liquid crystal display device is a cause of increasing the thickness of the liquid crystal display device.
[0008]
On the other hand, a liquid crystal display device composed of the above thin film device is formed on a lightweight and flexible substrate material such as a plastic substrate, and a demand for manufacturing a novel liquid crystal display device having deformability Is growing. In order to realize this, it is necessary to form a thin film device at a process temperature lower than the heat resistance temperature (100 to 150 ° C.) of the plastic substrate. However, a decrease in process temperature tends to cause a decrease in characteristics of the thin film device, and it is difficult to manufacture a high performance thin film device. In order to cope with this, a method of transferring the thin film device onto the plastic substrate by a technique for transferring the thin film device formed on the glass substrate (see, for example, JP-A-10-125931) has also been proposed.
[0009]
However, even if the thin film device can be formed on the plastic substrate by the above-described configuration procedure, the transmissive liquid crystal display device needs the backlight 200 as shown in FIG. It was difficult to manufacture what was provided.
[0010]
[Problems to be solved by the invention]
In order to solve such problems, an object of the present invention is to provide a semiconductor device having a small thickness of the entire device and having excellent deformability even when a backlight is incorporated, and a method for manufacturing the same. .
[0011]
Another object of the present invention is to provide a liquid crystal display device having a small overall thickness and excellent deformability by integrating a thin film surface-emitting light source with a thin film device, and a method for manufacturing the same. It is.
[0012]
Another object of the present invention is to integrate a thin film surface emitting light source and a thin film device on a substrate by applying a conventional transfer technique in order to obtain this liquid crystal display device.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is characterized in that a thin film device and a surface emitting light source are integrated on a substrate using a conventional transfer technique.
[0014]
That is, the thin film device manufactured on the first substrate is temporarily transferred onto the second substrate, and a thin film surface emitting light source is formed on the back surface of the thin film device exposed at this time. Further, the thin film device provided with the surface-emitting light source is transferred to the third substrate. By selecting a flexible and deformable substrate as the third transfer substrate, a display device with a built-in backlight that can be deformed can be obtained without increasing the thickness of the entire device.
[0015]
A typical thin film device includes a common electrode provided over the entire light emitting surface for forming a liquid crystal display element, a pixel switching thin film transistor arranged in a matrix, and a scan connected to the gate of the thin film transistor. A line, a data line connected to the source of the thin film transistor, and a pixel electrode connected to the drain of the thin film transistor.
[0016]
The thin film device includes a driving circuit for driving the thin film transistor for pixel switching. The allowable thickness of the thin film device and the allowable thickness of the entire liquid crystal display device incorporating the backlight are not particularly limited, but it is preferably about 0.5 to 5.0 mm as the thin film device.
The surface-emitting light source is preferably an organic or inorganic electroluminescent element. One example thereof is an electroluminescent element that emits monochromatic light throughout a region that is not patterned with respect to matrix-like pixels. When a non-patterned light emitting element is used as a backlight, the liquid crystal display element includes a color filter corresponding to the pixel region.
[0017]
Another example of the surface-emitting light source is an organic or inorganic electroluminescent element, which is patterned for each of the matrix-like pixels, and each color of RGB is arranged in a predetermined order and color-separated light is emitted. As an organic or inorganic electric field element, an electroluminescence (EL) element is most suitable.
[0018]
Since the electroluminescent element can be formed with a thickness of several μm to several tens of μm, the entire apparatus is formed by forming an electroluminescent element as a surface-emitting light source on the back surface of the thin film device and transferring it to a flexible substrate. Thus, it is possible to obtain a semiconductor device that does not increase in thickness and is excellent in flexibility. In addition, the organic electroluminescent device can be manufactured at a low temperature and with a simple process.
[0019]
In order to control the transmission / non-transmission of the light projected from the backlight by the liquid crystal, the projection light must have a polarization characteristic. Therefore, preferably, if the light itself projected from the backlight has polarization characteristics, the polarizing plate on the backlight side can be omitted and the thickness of the device can be reduced accordingly.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram of a liquid crystal display device with built-in backlight (hereinafter simply referred to as a liquid crystal display device) 10. The liquid crystal display device 10 is roughly divided into a liquid crystal display unit 12 and a thin film device (TFT). It is classified into a part 14, a backlight part 16, and a substrate 17.
[0021]
The liquid crystal display device 10 of FIG. 1 is a so-called monochrome image display device that performs only gradation expression by the liquid crystal display unit 12, whereas FIGS. 2 and 3 show a liquid crystal for displaying a color image. A display device 10 is shown.
[0022]
FIG. 2 shows a color filter 18 of each color (RGB) arranged in a matrix according to a predetermined rule corresponding to each pixel formed on the TFT unit 14 on the surface of the liquid crystal display unit 12 and surrounding these. 1 shows a display device provided with a filter section 22 composed of a black matrix frame 20 provided.
[0023]
Further, FIG. 3 shows that EL (electroluminescence) as an electroluminescence element applied as the backlight unit 16 is formed in a bank 24 corresponding to each pixel of the TFT unit 14, and each color ( The configuration in which the backlight unit 16 itself emits light to each color of RGB by filling the RGB component is shown.
[0024]
Since the basic structure of the liquid crystal display device 10 shown in FIG. 1 to FIG. 3 does not change, first, the detailed configuration will be described taking the color image liquid crystal display device 10 shown in FIG. 2 as an example.
[0025]
FIG. 4 shows a detailed configuration of the liquid crystal display device 10 with a built-in backlight shown in FIG.
[0026]
In the liquid crystal display device 10, in the product stage, the third substrate 25 serves as a basic support layer, and the layers constituting the backlight unit 16, the TFT unit 14, and the liquid crystal display unit 12 are laminated. Note that the first substrate 100 and the second substrate 180 (refer to the process diagrams of FIGS. 5 to 13) are applied in the middle of stacking of the respective parts on the third substrate, that is, in the manufacturing stage. It is like that.
[0027]
The backlight unit 16 has a configuration in which an EL layer 32 is sandwiched between the electron transport layer 28 and the hole transport layer 30. An ITO layer 34 is provided on the upper layer of the hole transport layer 30. That is, when an electric field (voltage) is applied between the ITO layer 34 and the base electrode layer 26, a current flows through the EL layer 32 and functions as a backlight. The light emitted from the EL layer 32 has a polarization direction set to a fixed direction. As a result, one of the pair of polarizing plates necessary for liquid crystal display is omitted, and the surface light emission is directly applied to the back surface of the thin film device. A mold light source can be provided. As a method for enabling this, for example, a rubbing process can be given. The rubbing process is described in detail in, for example, the IEICE Technical Report E1D95-106 (issued in 1995).
[0028]
A transparent intermediate layer 36 is provided on the ITO layer 34, and the TFT section 14 as a thin film device is disposed on the intermediate layer 36.
[0029]
The TFT section 14 forms a matrix in which a TFT array 38 is provided for each pixel. The TFT array 38 includes a drain electrode 38D, a gate electrode 38G, and a source electrode 38S. Further, the source / drain regions 39D and 39S correspond to the drain electrode 38D and the source electrode 38S, and the active silicon region 39G corresponds to the gate electrode 38G. A transparent pixel electrode (arranged corresponding to each pixel) 40 is provided for each TFT array 38.
[0030]
In addition, a pair of alignment films 44 and 46 in which a liquid crystal 42 is sealed in an intermediate space via a planarizing film 41 are provided above the pixel electrode 40. The liquid crystal 42 is filled in the entire pixel region and sealed with a sealing agent 47 so that it does not leak.
[0031]
A counter electrode 48 is provided on the upper surface of the upper alignment film 46, and an electric field (voltage) is applied between the pixel electrode 40 and the common electrode 48, whereby the alignment of the liquid crystal 42 depends on the applied voltage. Changes to a predetermined transmittance for light having a predetermined polarization direction passing between the pair of alignment films 44 and 46.
[0032]
On the upper surface of the common electrode 48, a counter substrate 49 and a polarizing plate 50 are provided in this order via a color filter layer 52. The polarizing plate 50 can pass only light in the predetermined polarization direction, and emits light with a light amount based on the transmittance set by the alignment of the liquid crystal 42 with respect to 100% of the light amount emitted from the EL layer 32. It is supposed to be.
[0033]
The color filter layer 52 is configured by a filter unit in which filters of RGB colors are arranged in order corresponding to each pixel, and if necessary, a non-light-emitting region of each pixel (a region where the TFT array 38 is disposed, etc.) ) In a non-transparent state, and includes a black matrix portion for improving color separation of each pixel.
[0034]
In the above configuration, the third substrate 25 is configured by a flexible transparent synthetic resin (plastic or the like) plate, whereby the backlight built-in liquid crystal display device 10 according to the present embodiment is configured as follows. It is possible to dispose on a support having a curved surface without having to maintain a flat surface.
[0035]
An example of such a curved support is a dome (hemispherical) type ceiling. The backlight type built-in type liquid crystal display device 10 can be arranged on such a dome-shaped ceiling to constitute a planetarium. Further, a 360-degree panoramic image can be displayed by disposing the backlight type built-in liquid crystal display device 10 over the entire inner peripheral surface of the cylindrical room.
[0036]
By the way, since it is difficult to form the TFT portion 14 from the beginning by using a flexible substrate as the third substrate 25 from the viewpoint of process temperature, photolithography accuracy, etc., the transfer technique described above is used. Apply.
[0037]
5 to 13 are diagrams for forming the TFT section 14. Since the detailed manufacturing process of the TFT array 38 is known, the description thereof is omitted.
[0038]
[Process 1]
As shown in FIG. 5, a first separation layer (light absorption layer) 120 as a first release layer is formed on the first substrate 100.
[0039]
Hereinafter, the first substrate 100 and the first separation layer 120 will be described.
(Description of the first substrate 100)
The first substrate 100 preferably has a light-transmitting property that allows light to pass therethrough.
[0040]
In this case, the light transmittance is preferably 10% or more, and more preferably 50% or more. If this transmittance is too low, the attenuation (loss) of light increases, and a larger amount of light is required to peel off the first separation layer 120.
[0041]
Further, the first substrate 100 is preferably made of a highly reliable material, and particularly preferably made of a material having excellent heat resistance. The reason is that, for example, when forming a TFT layer 140 described later (corresponding to the TFT portion 14 in FIG. 4), the process temperature may be high (for example, about 350 to 1200 ° C.) depending on the type and formation method. Even in such a case, if the first substrate 100 is excellent in heat resistance, the range of setting of film forming conditions such as the temperature condition is widened when forming the TFT layer 140 or the like on the first substrate 100. It is.
[0042]
Therefore, the first substrate 100 is preferably made of a material having a strain point equal to or higher than Tmax, where Tmax is the maximum temperature when forming the TFT layer 140. Specifically, the constituent material of the first substrate 100 preferably has a strain point of 350 ° C. or higher, and more preferably 500 ° C. or higher. As such a thing, heat resistant glass, such as quartz glass, Corning 7059, Nippon Electric Glass OA-2, is mentioned, for example.
[0043]
Further, the thickness of the first substrate 100 is not particularly limited, but it is usually preferably about 0.1 to 5.0 mm, and more preferably about 0.5 to 1.5 mm. If the thickness of the first substrate 100 is too thin, the strength is reduced, and if it is too thick, light attenuation tends to occur when the transmittance of the first substrate 100 is low. When the light transmittance of the first substrate 100 is high, the thickness may exceed the upper limit value. Note that the thickness of the first substrate 100 is preferably uniform so that light can be irradiated uniformly.
(Description of the first separation layer 120)
The first separation layer 120 has such a property that it absorbs irradiated light and causes peeling (hereinafter referred to as “in-layer peeling” or “interfacial peeling”) within the layer and / or at the interface. Preferably, the bonding force between the atoms or molecules of the substance constituting the first separation layer 120 disappears or decreases by light irradiation, that is, ablation occurs, leading to in-layer separation and / or interfacial separation. Things are good.
[0044]
Furthermore, the gas may be emitted from the first separation layer 120 by light irradiation, and the separation effect may be exhibited. That is, when the component contained in the first separation layer 120 is released as a gas, and when the first separation layer 120 absorbs light and becomes a gas for a moment, its vapor is released and contributes to the separation. There are cases. Examples of the composition of the first separation layer 120 include those described in the following A to E.
[0045]
A. Amorphous silicon (a-Si)
B. Various oxide ceramics such as silicon oxide or silicate compound, titanium oxide or titanate compound, zirconium oxide or zirconate compound, lanthanum oxide or lanthanum oxide compound, electrical conductor (ferroelectric material) or semiconductor
C. Ceramics or dielectrics such as PZT, PLZT, PLLZT, PBZT (ferroelectric)
D. Nitride ceramics such as silicon nitride, aluminum nitride, titanium nitride
E. Organic polymer materials
F. metal
The thickness of the first separation layer 120 varies depending on various conditions such as the purpose of peeling, the composition of the first separation layer 120, the layer structure, and the formation method, but it is usually preferably about 1 nm to 20 μm. It is more preferably about ˜2 μm, and further preferably about 40 nm to 1 μm. If the thickness of the first separation layer 120 is too small, the uniformity of film formation may be impaired and peeling may be uneven. If the film thickness is too thick, the good separation of the first separation layer 120 is obtained. In order to ensure the above, it is necessary to increase the light power (light amount), and it takes time to remove the first separation layer 120 later. Note that the thickness of the first separation layer 120 is preferably as uniform as possible.
[0046]
The formation method of the 1st separated layer 120 is not specifically limited, According to various conditions, such as a film | membrane composition and a film thickness, it selects suitably. For example, CVD (including MOCVD, low pressure CVD, ECR-CVD), vapor deposition, molecular beam vapor deposition (MB), sputtering, ion plating, PVD and other various vapor deposition methods, electroplating, immersion plating (dipping), Various plating methods such as electroless plating, Langmuir Projet (LB) method, spin coating, spray coating, roll coating and other coating methods, various printing methods, transfer methods, ink jet methods, powder jet methods, etc. Two or more of them can be combined to form.
[0047]
For example, when the composition of the first separation layer 120 is amorphous silicon (a-Si), it is preferable to form the film by CVD, particularly low-pressure CVD or plasma CVD.
[0048]
Further, when the first separation layer 120 is made of a ceramic by a sol-gel method or an organic polymer material, it is preferable to form a film by a coating method, particularly by spin coating.
[0049]
[Process 2]
Next, as shown in FIG. 6, the TFT layer 140 is formed on the first separation layer 120.
[0050]
An enlarged cross-sectional view of the K portion of the TFT layer 140 (the portion surrounded by the one-dot chain line in FIG. 6) is shown on the right side of FIG. As shown in the figure, the TFT layer 140 includes a TFT array (thin film transistor) 38, and the TFT array 38 is formed by introducing an n-type impurity or a P-type impurity into a polysilicon layer. Regions 58 and 60, a gate insulating film layer 62, a gate electrode 64, a gate electrode line 66 made of aluminum, for example, and a drain electrode line 68 are provided.
[0051]
In the present embodiment, Si0 is used as an intermediate layer provided in contact with the first separation layer 120. ₂ Although a film is used, other insulating films such as Si3N4 can also be used. The thickness of the SiO2 film (intermediate layer) is appropriately determined according to the purpose of formation and the function that can be exerted, but it is usually preferably about 10 nm to 5 μm, and preferably about 40 nm to 1 μm. More preferred. The intermediate layer is formed for various purposes, and functions as, for example, a protective layer that physically or chemically protects the TFT 140, an insulating layer, a conductive layer, a laser light shielding layer, a barrier layer for preventing migration, and a reflective layer. The thing which exhibits at least 1 of these is mentioned.
[0052]
In some cases, Si0 ₂ The TFT layer 140 may be formed directly on the first separation layer 120 without forming an intermediate layer such as a film.
[0053]
The TFT layer 140 is a layer including a thin film device such as a TFT as shown on the right side of FIG.
[0054]
[Process 3]
Next, as shown in FIG. 7, a second separation layer (for example, a hot-melt adhesive layer) 160 as a second release layer is formed on the TFT layer 140. Note that the second separation layer 160 can also be formed of an ablation layer in the same manner as the first separation layer 120.
[0055]
As this second separation 160, for example, an electron wax such as a proof wax (trade name) that is less likely to contaminate the thin film device with impurities (sodium, potassium, etc.). A water-soluble adhesive is also applicable.
[0056]
[Process 4]
Further, as shown in FIG. 7, the second substrate 180 is bonded on the second separation layer 160. Since the second substrate 180 is bonded after the TFT layer 140 is manufactured, there is no restriction on the process temperature or the like at the time of manufacturing the TFT layer 140, and it is sufficient that the mold retainability is at room temperature. In this embodiment mode, a material that is relatively inexpensive and has shape retention properties such as a glass substrate and a synthetic resin is used.
[0057]
[Process 5]
Next, as shown in FIG. 8, light is irradiated from the back side of the first substrate 100.
[0058]
This light is applied to the first separation layer 120 after passing through the first substrate 100. As a result, in-layer separation and / or interface separation occurs in the first separation layer 120, and the bonding force decreases or disappears.
[0059]
The principle that intralayer separation and / or interfacial separation occurs in the first separation layer 120 is that ablation occurs in the constituent material of the first separation layer 120, the gas contained in the first separation layer 120 is released, Is estimated to be due to phase changes such as melting and transpiration that occur immediately after irradiation.
[0060]
Here, the ablation means that a fixing material that absorbs irradiation light (a constituent material of the first separation layer 120) is photochemically or thermally excited, and a bond between atoms or molecules inside the surface or inside is cut and emitted. In general, all or part of the constituent material of the first separation layer 120 appears as a phenomenon that causes a phase change such as melting or transpiration (vaporization). In addition, the phase change may result in a minute firing state, which may reduce the binding force.
[0061]
Whether the first separation layer 120 causes in-layer separation, interfacial separation, or both depends on the composition of the first separation layer 120 and various other factors, and is one of the factors. The conditions such as the type of light to be irradiated, the wavelength, the intensity, and the reaching depth can be mentioned.
[0062]
The irradiation light may be any light as long as it causes internal separation and / or interfacial separation in the first separation layer 120. For example, X-rays, ultraviolet rays, visible light, infrared rays (heat rays), laser light, Examples include millimeter waves, microwaves, electron beams, radiation (α rays, β rays, γ rays) and the like. Among these, a laser beam is preferable and an excimer laser is more preferably used from the viewpoint that peeling (ablation) of the first separation layer 120 is likely to occur.
[0063]
Next, as shown in FIG. 9, a force is applied to the first substrate 100 to separate the first substrate 100 from the first separation layer 120. Although not shown in FIG. 9, the first separation layer 120 may adhere to the first substrate 100 after the separation.
[0064]
[Step 6]
Next, as shown in FIG. 10, the remaining first separation layer 120 is removed by a method such as cleaning, etching, ashing, polishing, or a combination thereof. As a result, the TFT layer 140 is transferred to the second substrate 180.
[0065]
[Step 7]
Next, as shown in FIG. 11, the third substrate 200 in which the backlight 150 (same as the backlight portion 16 in FIG. 4) is formed on the lower surface (exposed surface) of the TFT layer 140 via the adhesive layer 190. Glue. At this time, the upper surface of the backlight 150 is rubbed. Alternatively, the backlight 150 may be formed immediately below the TFT layer 140 in advance, and the adhesive layer 190 may be provided between the backlight 150 and the third substrate 200 and attached. In this case, the lower surface of the backlight 150 is rubbed.
[0066]
The backlight unit 16 applied to this embodiment does not need to be patterned in a matrix, and EL is applied as an electroluminescent element that emits monochromatic light throughout the entire area. In this EL, since it is sufficient to emit light entirely in accordance with the image display region, a frame-like wall is formed so as to surround the light emitting region, and a fluorescent material is applied to the base surface by, for example, an ink jet method.
[0067]
Preferable examples of the adhesive constituting the adhesive layer 190 include various curable types such as a reactive curable adhesive, a thermosetting adhesive, a photocurable adhesive such as an ultraviolet curable adhesive, and an anaerobic curable adhesive. An adhesive is mentioned. The composition of the adhesive may be any, for example, epoxy, acrylate, or silicone. Such an adhesive layer 190 is formed by, for example, a coating method.
[0068]
In the case of using the curable adhesive, for example, a curable adhesive is applied to the lower surface of the TFT layer 140, the backlight unit 150 is adhered, and further, the cured adhesive is applied to the backlight unit 150, and the third substrate 200. Then, the curable adhesive is cured by a curing method according to the characteristics of the curable adhesive, and the TFT layer 140, the backlight unit 150, and the third substrate 200 are bonded and fixed.
[0069]
When the adhesive is a photo-curing type, light is preferably applied from the outside of the light-transmitting third substrate 200. As the adhesive, if a light curable adhesive such as an ultraviolet curable adhesive that does not affect the thin film device layer is used, the light transmissive second substrate 180 side or the light transmissive second and third materials are used. Light may be irradiated from both sides of the substrates 180 and 200.
[0070]
There is no restriction | limiting in particular as a 3rd board | substrate, As a result, it also becomes possible to apply the transparent substrate which has flexibility.
[0071]
[Step 8]
Next, as shown in FIG. 12, the second separation layer 160 is heated or immersed in water and melted. As a result, since the adhesive force of the second separation layer 160 is weakened, the second substrate 180 can be detached from the TFT layer 140. Note that by removing the second separation layer 160 attached to the second substrate 180, the second substrate 180 can be reused repeatedly.
[0072]
[Step 9]
Finally, by removing the second separation layer 160 attached to the surface of the TFT layer 140, the TFT layer 140 having the light emitting layer transferred to the third substrate 200 is obtained as shown in FIG. Can do. Here, the surface layer relationship of the TFT layer 140 with respect to the third substrate 200 is the same as the surface layer relationship of the TFT layer 140 with respect to the initial first substrate 100 as shown in FIG.
[0073]
Thereafter, the liquid crystal display unit 14 is formed on the TFT layer 140 and the color filter layer 52 is provided, whereby the backlight built-in liquid crystal display device 10 is completed.
[0074]
Through the above steps, the transfer of the TFT layer 140 to the third substrate 200 is completed. Then, SiO adjacent to the TFT layer 140 ₂ Removal of the film, formation of a conductive layer such as a wiring on the TFT layer 140, or a desired protective film can also be performed.
[0075]
In the present invention, the TFT layer 140 itself, which is an object to be peeled off, is not directly peeled off, but is separated at the first separation layer 120 and the second separation layer 160 and transferred to the third substrate 200. Regardless of the characteristics, conditions, etc., transfer can be performed easily, reliably and uniformly, and the TFT layer 140 can be maintained at high reliability without damage to the TFT layer 140 due to the separation operation.
[0076]
Further, a water-soluble material can be used as an adhesive when the thin film device is bonded to the second substrate. A surface-emitting backlight is bonded to the back surface of the thin film device, which is transferred to the second substrate and exposed on the back surface, via a water-insoluble adhesive. Next, when the device in this state is immersed in water, the water-soluble adhesive is dissolved in water, and the thin film device is transferred to the third substrate together with the thin film backlight.
[0077]
Alternatively, a thin film backlight may be provided on the third substrate, and the back surface of the thin film device may be adhered on the backlight, and then the thin film device may be peeled from the second substrate.
(Other embodiments)
In the liquid crystal display device 10 with a built-in backlight in the above embodiment, the color filter layer 22 is provided on the upper layer, thereby enabling full color image display together with gradation expression of the liquid crystal display unit 12. There is a configuration in which full color image display is possible without providing the layer 22 (see FIG. 2).
[0078]
That is, as shown in FIG. 14, the EL layer 32 of the backlight unit 16 is divided by the bank 32A for each pixel matrix formed by the TFT unit 14, and elements (light emitting layer formation) for emitting light in RGB colors in advance. The solution for preparation) is injected. In this case, RGB colors are arranged side by side in the vertical or horizontal direction, and by repeating these arrangements, it is possible to perform color display with the original three pixels as one pixel.
[0079]
As a method for constructing the light emitting layer for each of the RGB colors, there are the following methods.
A method of forming a colored layer by filling a solution for forming a light emitting layer by an inkjet method and drying the solution.
A method in which a colored resist layer is formed on an underlayer, and the colored resist layer is exposed to light and developed with a photomask in units of pixel areas, thereby forming a colored layer corresponding to the pixel area.
A light emitting layer is applied to the underlayer, and a resist layer is formed thereon. Then, the resist layer is exposed and developed in a photomask for each pixel area, and the light emitting layer is etched from the resist layer corresponding to the pixel area. And peeling the resist layer to form a colored layer corresponding to the pixel region.
A method of forming a colored layer corresponding to a pixel region by attaching a light emitting layer to a base layer by a printing method for each pixel region.
[0080]
Further, in the case of monochrome display, an image is formed by gradation expression by the liquid crystal display unit, and thus the above color filter is not required at all. That is, in the configuration of FIG. 4, the color filter layer 52 is excluded. In monochrome display, one image data is generated with three pixels in color display, whereas one image data with one pixel is sufficient, so the resolution is tripled.
[0081]
According to the present embodiment, in the configuration in which the thin film device is provided with the drive circuit made of TFT, it is not necessary to use an external circuit such as an LSI as the drive circuit, and the restriction caused by connecting the external circuit to the liquid crystal display device is avoided And the selection range of a suitable material as a 3rd board | substrate can be expanded. Circuits necessary for the liquid crystal display device (active matrix and driving circuit) can be embedded on a single flexible substrate (on the third substrate), and the advantages such as reduction in the number of components can be exhibited. it can.
[0082]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a semiconductor device having a small thickness of the entire device and having excellent deformability even when a backlight is incorporated, and a manufacturing method thereof.
[0083]
Furthermore, according to the present invention, by integrating a thin-film surface-emitting light source with a thin film device, a liquid crystal display device having a small overall thickness and excellent deformability and a method for manufacturing the same can be provided. .
[0084]
Furthermore, according to the present invention, in order to obtain this liquid crystal display device, a thin film surface emitting light source and a thin film device can be integrated on a substrate by applying a conventional transfer technique.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram (monochrome type) of a liquid crystal display device with a built-in backlight according to the present embodiment.
FIG. 2 is a conceptual diagram (full color type using a filter) of a liquid crystal display device with a built-in backlight according to the present embodiment.
FIG. 3 is a conceptual diagram of a liquid crystal display device with a built-in backlight according to the present embodiment (full color type by color separation of a built-in light source).
4 is a detailed configuration diagram of the liquid crystal display device with a built-in backlight shown in FIG. 2. FIG.
FIG. 5 is a manufacturing process diagram (step 1) for forming a TFT portion;
FIG. 6 is a manufacturing process diagram (step 2) for forming a TFT portion;
FIG. 7 is a manufacturing process diagram (step 3) for forming a TFT portion;
FIG. 8 is a manufacturing process diagram (step 4) for forming a TFT portion;
FIG. 9 is a manufacturing process diagram (step 5) for forming a TFT portion;
FIG. 10 is a manufacturing process diagram (step 6) for forming a TFT portion;
FIG. 11 is a manufacturing process diagram (step 7) for forming the TFT portion;
FIG. 12 is a manufacturing process diagram (step 8) for forming the TFT portion;
FIG. 13 is a manufacturing process diagram (step 9) for forming the TFT portion;
14 is a detailed configuration diagram of the liquid crystal display device with a built-in backlight shown in FIG. 3. FIG.
FIG. 15 is an exploded perspective view showing a configuration of a conventional liquid crystal display device with a backlight.
[Explanation of symbols]
10 Backlight built-in liquid crystal display device
12 Liquid crystal display
14 TFT section
16 Backlight section
22 Color filter layer
25 Third substrate
26 EL layer
40 Transparent pixel electrode
38 TFT array
42 liquid crystal
48 Counter electrode
52 Color filter layer
100 first substrate
180 Second substrate
200 Third substrate

Claims (13)

A liquid crystal display device comprising a thin film device comprising a semiconductor circuit, wherein a thin-film surface-emitting light source is formed at the interface between the thin film device and the substrate. 2. The backlight built-in liquid crystal display device according to claim 1, wherein the surface-emitting light source is an organic or inorganic electroluminescent element. The thin film device is connected to a pixel switching transistor arranged in a matrix, a scanning line connected to a gate of the thin film transistor, a data line connected to a source of the thin film transistor, and a drain of the thin film transistor The liquid crystal display device with a built-in backlight according to claim 1, further comprising a pixel electrode and a drive circuit for driving the pixel switching thin film transistor, wherein a liquid crystal display element is formed on a surface of the thin film device. A first step of forming a release layer on the first substrate; a second step of forming a thin film device having matrix-like pixels on the release layer; and peeling the thin film device from the first substrate. Then, a third step of transferring onto the second substrate, a fourth step of forming a surface-emitting light source on the back surface of the thin film device exposed by being transferred onto the second substrate, A backlight built-in type comprising a fifth step of peeling the thin film device from the second substrate and transferring it onto a third substrate, and a sixth step of forming a liquid crystal display element on the surface of the thin film device A method for manufacturing a liquid crystal display device. A first step of forming a release layer on the first substrate; a second step of forming a thin film device having matrix-like pixels on the release layer; and peeling the thin film device from the first substrate. Then, a third step of transferring onto the second substrate, a fourth step of forming a surface-emitting light source on the third substrate, and a step of bonding the surface-emitting light source and the back surface of the thin film device. 5. Manufacturing of a backlight built-in type liquid crystal display device comprising: a step 5; a sixth step of peeling the thin film device from the second substrate; and a seventh step of forming a liquid crystal display element on the surface of the thin film device. Method. In the invention of claim 4 or claim 5, the thin film device is connected to a common electrode provided over the entire light emitting surface, a pixel switching thin film transistor arranged in a matrix, and a gate of the thin film transistor. 7. A scanning line, a data line connected to a source of the thin film transistor, a pixel electrode connected to a drain of the thin film transistor, and a drive circuit for driving the thin film transistor for pixel switching. The method described. 7. The method according to claim 4, wherein the surface-emitting light source is an organic or inorganic electroluminescent element, and the entire region is monochromaticly emitted without being patterned with respect to the matrix pixel. The method according to claim 7, wherein the liquid crystal display element includes a color filter corresponding to the pixel region. 8. The surface emitting light source according to claim 4, wherein the surface-emitting light source is an organic or inorganic electroluminescent element, is patterned for each of the matrix pixels, and each color of RGB is in a predetermined order. The method according to claim 1, wherein the light is separated and emitted by color separation. The method according to claim 4, wherein the third substrate is made of a flexible material. The method of claim 10, wherein the third substrate is a plastic substrate. The method according to claim 4, wherein light projected from the surface-emitting light source has a polarization characteristic. A liquid crystal display device with a built-in backlight manufactured by the method according to claim 1.

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