WO2021005798A1

WO2021005798A1 - Method for manufacturing flexible light emitting device and support substrate

Info

Publication number: WO2021005798A1
Application number: PCT/JP2019/027580
Authority: WO
Inventors: 克彦岸本
Original assignee: 堺ディスプレイプロダクト株式会社
Priority date: 2019-07-11
Filing date: 2019-07-11
Publication date: 2021-01-14

Abstract

According to the method for manufacturing a flexible light emitting device of the present disclosure, a laminate structure (100) is prepared that comprises: a base (10); a functional layer region (20) including a TFT layer and a light-emitting element layer; a flexible film (30) positioned between the base and the functional layer region and supporting the functional layer region; and a release layer (12) positioned between the flexible film and the base and fixed to the base. The release layer is irradiated with peeling light (216) passing through the base, to peel off the flexible film from the release layer. The release layer is formed of an alloy of aluminum and silicon.

Description

Manufacturing method of flexible light emitting device and support substrate

The present disclosure relates to a method for manufacturing a flexible light emitting device and a support substrate.

Typical examples of flexible displays are films formed from synthetic resins such as polyimide (hereinafter referred to as "resin films"), TFTs (Thin Film Transistors) and OLEDs (Organic Light Emitting Diodes) supported by the resin films. It is equipped with the element of. The resin film functions as a flexible substrate. Since the organic semiconductor layer constituting the OLED is easily deteriorated by water vapor, the flexible display is sealed with a gas barrier film (sealing film).

The flexible display can be manufactured using a glass base having a resin film formed on the upper surface. The glass base functions as a support (carrier) that maintains the shape of the resin film flat during the manufacturing process. By forming a light emitting element such as a TFT element and an OLED, a gas barrier film, and the like on the resin film, a flexible display structure is realized while being supported by a glass base. The flexible display is then stripped from the glass base to gain flexibility. The portion where the light emitting elements such as the TFT element and the OLED are arranged can be referred to as a "functional layer region" as a whole.

Patent Document 1 discloses a method of irradiating the interface between the flexible substrate and the glass base with an ultraviolet laser beam in order to peel off the flexible substrate on which the light emitting device is placed from the glass base. In the method disclosed in Patent Document 1, an amorphous silicon layer is arranged between the flexible substrate and the glass base. Irradiation with ultraviolet laser light generates hydrogen from the amorphous silicon layer and peels the flexible substrate from the glass base.

International Publication No. 2009/0377797

Conventionally, since the resin film used for the flexible substrate absorbs ultraviolet rays, the influence of the peeling light irradiation on the TFT element and the light emitting element has not been particularly investigated. However, according to the study by the present inventor, it has been found that the strong peeling light used in the peeling step may deteriorate the TFT element and the light emitting element.

Such a problem is not limited to the flexible display having an OLED as a light emitting element, and may occur in the manufacture of a flexible light emitting device having a micro LED (μLED) formed from an inorganic semiconductor material as a light emitting element.

The present disclosure provides a new manufacturing method and a support substrate for a flexible light emitting device that can solve the above problems.

In an exemplary embodiment, the method of manufacturing a flexible light emitting device of the present disclosure is located between a base, a functional layer region including a TFT layer and a light emitting element layer, and the base and the functional layer region. A step of preparing a laminated structure including a flexible film that supports a layer region and a release layer that is located between the flexible film and the base and is fixed to the base, and ultraviolet rays that pass through the base. The step of irradiating the release layer with the release light to peel the flexible film from the release layer is included. The release layer is formed of an alloy of aluminum and silicon.

In certain embodiments, the ultraviolet exfoliation light is non-coherent light.

In certain embodiments, the light emitting element layer includes a plurality of arranged micro LEDs, and the ultraviolet exfoliation light is laser light.

In a certain embodiment, the weight ratio of silicon contained in the alloy is 4% or more and 20% or less.

In a certain embodiment, the coefficient of linear expansion of the release layer is 30% or more and 500% or less of the coefficient of linear expansion of the flexible film.

In a certain embodiment, the thickness of the release layer is 100 nm or more and 5000 nm or less.

In a certain embodiment, the wavelength of the ultraviolet exfoliation light is 300 nm or more and 360 nm or less.

In a certain embodiment, the thickness of the flexible film is 5 μm or more and 20 μm or less.

In certain embodiments, the steps of preparing the laminated structure include a step of forming the release layer on the base by sputtering an aluminum target containing silicon, and a step of forming the flexible film on the release layer. Including the process.

In a certain embodiment, the step of peeling the flexible film from the release layer and then removing the release layer from the base and recovering the film is included.

The support substrate of the present disclosure is, in an exemplary embodiment, a support substrate for a flexible light emitting device, a base formed of a release layer made of an alloy of aluminum and silicon and a material that transmits ultraviolet light. , With a base supporting the release layer.

In certain embodiments, a flexible film that covers the release layer and is formed of a material that transmits the ultraviolet rays is further provided.

According to the embodiment of the present invention, a new manufacturing method and a support substrate of a flexible light emitting device that solves the above-mentioned problems are provided.

It is a top view which shows the structural example of the laminated structure used in the manufacturing method of the flexible light emitting device by this disclosure. FIG. 3 is a sectional view taken along line BB of the laminated structure shown in FIG. 1A. It is a process sectional view which shows the manufacturing method of the support substrate in embodiment of this disclosure. It is a process sectional view which shows the manufacturing method of the support substrate in embodiment of this disclosure. It is a process sectional view which shows the manufacturing method of the flexible light emitting device in embodiment of this disclosure. It is a process sectional view which shows the manufacturing method of the flexible light emitting device in embodiment of this disclosure. It is a process sectional view which shows the manufacturing method of the flexible light emitting device in embodiment of this disclosure. It is a process sectional view which shows the manufacturing method of the flexible light emitting device in embodiment of this disclosure. It is an equivalent circuit diagram of one sub-pixel in a flexible light emitting device. It is a perspective view of the laminated structure in the middle stage of a manufacturing process. It is sectional drawing which shows typically the division | division position of a laminated structure. It is a top view which shows typically the division | division position of a laminated structure. It is a figure which shows typically the state just before the stage supports a laminated structure. It is a figure which shows typically the state which a stage supports a laminated structure. It is a figure which shows typically the state which irradiates the interface between the base of a laminated structure and a resin film by the peeling light formed in a line shape. It is a perspective view which shows typically the state of irradiating the laminated structure with the line beam emitted from the line beam light source of a stripping apparatus. It is a figure which shows typically the position of the stage at the start of irradiation of the separation light. It is a figure which shows typically the position of the stage at the end of irradiation of the separation light. It is sectional drawing which shows typically the structural example of the surface light source which emits the separation light. It is a top view which shows the structural example of the surface light source. It is sectional drawing which shows typically the surface light source 215 including a plurality of light emitting diode elements arranged two-dimensionally. It is sectional drawing which shows the surface light source 215 which increased the in-plane number density of the light emitting diode element as compared with the example shown in FIG. It is a figure which shows the array of light emitting diode elements arranged in a row and a column. It is a figure which shows typically the upper surface of the line beam light source 214 which includes one row of light emitting diode elements arranged in the Y-axis direction. It is a BB line sectional view of the laminated structure shown in FIG. 13A. It is a figure which shows the moving direction of a line beam light source with respect to a laminated structure. It is a figure which shows typically the upper surface of the line beam light source 214 which includes a plurality of rows of light emitting diode elements arranged in the Y-axis direction. FIG. 14 is a sectional view taken along line BB of the line beam light source shown in FIG. 14A. It is a figure which shows the moving direction of a line beam light source with respect to a laminated structure. It is a top view schematically showing an example of a surface light source in which a large number of light emitting diode elements are arranged in a matrix. It is sectional drawing which shows typically the state before separating the laminated structure into a 1st part and 2nd part after irradiation of the peeling light. It is sectional drawing which shows typically the state which separated the laminated structure into the 1st part and the 2nd part.

Since Laser Lift Off (LLO) is performed to peel off the flexible substrate from the glass base, a release layer may or may not be provided between the glass base and the flexible substrate.

If the release layer is not provided, the manufacturing cost is reduced, but the peeling yield is reduced. More specifically, there is a problem that soot-like residues called ash, which are very difficult to remove, are formed on the surfaces of both the glass base and the flexible substrate when irradiated with strong light for peeling (peeling light). is there. This reduces the adhesion of the support film or the like attached to the flexible substrate after the laser lift-off process, and also prevents the glass base from being reused. Further, there is a problem that the irradiation condition range of the peeling light (for example, laser light) that can be appropriately peeled off is narrow. On the other hand, when the release layer is provided, the generation of ash is reduced and the range of the peeling light irradiation condition is relatively wide, so that the peeling yield is improved. The release layer is typically formed from amorphous silicon, but can also be formed from refractory metals (Mo, Cr, W, Ti, etc.).

Conventionally, flexible substrates have been formed from resin materials typified by polyimide. Since such a resin material absorbs ultraviolet rays, it has been considered that it is not necessary to particularly study the influence of the peeling light irradiation on the TFT element and the light emitting element. However, according to the study of the present inventor, when the thickness of the flexible substrate becomes very thin, about 5 μm to 15 μm, the ultraviolet rays may not be sufficiently absorbed, and the strong ultraviolet rays used in the peeling step may cause the TFT element and the light emitting element. It was found that it could deteriorate. This problem also occurred when a release layer made of amorphous silicon was provided. This is because amorphous silicon can transmit ultraviolet rays. However, when the release layer is formed from the refractory metal, the refractory metal absorbs or reflects ultraviolet rays and does not transmit them, so that the influence of the separation light irradiation on the TFT element and the light emitting element can be prevented. However, forming a release layer using a refractory metal leads to a significant increase in manufacturing costs.

The reason why amorphous silicon or refractory metal is used as the material of the release layer is its high melting point. That is, it has been considered that the release layer should be formed from a high melting point material in order to prevent the release layer from being melted by heat generated by irradiation with peeling light.

However, according to the study of the present inventor, it was found that even when the release layer is formed from an alloy of aluminum and silicon having a low melting point, the release layer is not melted by irradiation with peeling light. This is because aluminum, which is the main component, has a large specific heat and latent heat of melting, and is excellent in heat conduction. As a result, even if the release layer is locally heated by the release light irradiation, the generated heat is quickly conducted to the surroundings, and the release layer can be avoided from being destroyed. As will be described later, the alloy of aluminum and silicon has a feature that the coefficient of linear expansion is lower than that of pure aluminum due to the presence of silicon. Generally, the coefficient of linear expansion of metal is larger than the coefficient of linear expansion of glass. In particular, aluminum has a larger coefficient of linear expansion than molybdenum, which is a refractory metal. If the difference in the coefficient of thermal expansion between the release layer and the glass base is too large, there may be a problem that a part of the release layer is separated from the glass base due to internal stress or strain. However, the coefficient of thermal expansion of the alloy of aluminum and silicon can be adjusted in a wide range depending on the silicon content ratio. Further, by adjusting the deposition conditions of the aluminum alloy, the internal stress of the deposited film can be significantly reduced as compared with the internal stress of the refractory metal film (for example, 400 GPa). Therefore, by using an alloy of aluminum and silicon, the problem of peeling of the release layer can be solved. Furthermore, the ability to use an alloy of aluminum and silicon, which is cheaper than refractory metals, as the release layer offers various advantages. For example, refractory metal materials are difficult to recycle, and each glass base to which the release layer is attached must be landfilled and disposed of as industrial waste. On the other hand, the alloy of aluminum and silicon can be easily dissolved and removed by a chemical solution such as acid, so that the recyclability is improved. Therefore, even if the release layer is used, the manufacturing cost can be reduced as a whole.

Hereinafter, a method of manufacturing a flexible light emitting device and an embodiment of a manufacturing apparatus according to the present disclosure will be described with reference to the drawings. Examples of "light emitting devices" include displays and lighting devices. In the following description, more detailed description than necessary may be omitted. For example, detailed explanations of already well-known matters and duplicate explanations for substantially the same configuration may be omitted. This is to avoid unnecessary redundancy of the following description and to facilitate the understanding of those skilled in the art. The inventors provide the accompanying drawings and the following description for those skilled in the art to fully understand the present disclosure. These are not intended to limit the subject matter described in the claims.

<Laminated structure>
See FIGS. 1A and 1B. In the method for manufacturing a flexible light emitting device in the present embodiment, first, the laminated structure 100 exemplified in FIGS. 1A and 1B is prepared. 1A is a plan view of the laminated structure 100, and FIG. 1B is a sectional view taken along line BB of the laminated structure 100 shown in FIG. 1A. For reference, FIGS. 1A and 1B show an XYZ coordinate system having an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other.

The laminated structure 100 in the present embodiment is located between the base (mother substrate or carrier) 10, the functional layer region 20 including the TFT layer 20A and the light emitting element layer 20B, and the base 10 and the functional layer region 20. A flexible film 30 that supports the functional layer region 20 and a release layer 12 that is located between the flexible film 30 and the base 10 and is fixed to the base 10 are provided. The release layer 12 is formed of an alloy of aluminum and silicon. The laminated structure 100 further includes a protective sheet 50 that covers the plurality of functional layer regions 20, and a gas barrier film 40 that covers the entire functional layer region 20 between the plurality of functional layer regions 20 and the protective sheet 50. I have. The laminated structure 100 may have other layers (not shown) such as a buffer layer.

The light emitting element layer 20B in the present embodiment has, for example, a plurality of OLED elements arranged two-dimensionally. The "light emitting element layer" in the present disclosure means a two-dimensional array of light emitting elements. The individual light emitting element is not limited to the OLED element, and may be a micro LED element. A typical example of the flexible light emitting device in the present embodiment is a "flexible display", but it may be a "flexible lighting device".

A typical example of the base 10 is a glass base having rigidity. A typical example of the flexible film 30 is a synthetic resin film having flexibility. Hereinafter, the "flexible film" is simply referred to as a "resin film". The structure including the release layer 12 and the base 10 supporting the release layer 12 is referred to as a "support substrate" of the flexible light emitting device as a whole. The support substrate may further include another film (eg, a flexible film) that covers the release layer 12.

The first surface 100a of the laminated structure 100 in the present embodiment is defined by the base 10, and the second surface 100b is defined by the protective sheet 50. The base 10 and the protective sheet 50 are members that are temporarily used during the manufacturing process, and are not elements that constitute the final flexible light emitting device.

The illustrated resin film 30 includes a plurality of flexible substrate regions 30d each supporting the plurality of functional layer regions 20, and an intermediate region 30i surrounding the individual flexible substrate regions 30d. The flexible substrate region 30d and the intermediate region 30i are merely different portions of one continuous resin film 30, and do not need to be physically distinguished. In other words, in the resin film 30, the portion located directly below each functional layer region 20 is the flexible substrate region 30d, and the other portion is the intermediate region 30i.

Each of the plurality of functional layer areas 20 finally constitutes a panel of a flexible light emitting device (for example, a "display panel"). In other words, the laminated structure 100 has a structure in which one base 10 supports a plurality of flexible light emitting devices before division. Each functional layer region 20 has a shape having a thickness (Z-axis direction size) of several tens of μm, a length (X-axis direction size) of about 12 cm, and a width (Y-axis direction size) of about 7 cm, for example. doing. These sizes can be set to any size depending on the size of the required display screen. The shape of each functional layer region 20 in the XY plane is rectangular in the illustrated example, but is not limited thereto. The shape of each functional layer region 20 in the XY plane may be a square, a polygon, or a shape including a curved line in the contour.

As shown in FIG. 1A, the flexible substrate region 30d is two-dimensionally arranged in rows and columns corresponding to the arrangement of the flexible light emitting devices. The intermediate region 30i is composed of a plurality of orthogonal stripes and forms a lattice pattern. The width of the stripe is, for example, about 1 to 4 mm. The flexible substrate region 30d of the resin film 30 functions as a “flexible substrate” for each flexible light emitting device in the form of a final product. On the other hand, the intermediate region 30i of the resin film 30 is not an element constituting the final product.

In the embodiment of the present disclosure, the configuration of the laminated structure 100 is not limited to the illustrated example. The number of functional layer regions 20 (the number of light emitting devices) supported by one base 10 does not have to be plural, and may be singular. When the functional layer region 20 is singular, the intermediate region 30i of the resin film 30 forms a simple frame pattern that surrounds one functional layer region 20.

Note that the size or ratio of each element described in each drawing is determined from the viewpoint of comprehensibility and does not necessarily reflect the actual size or ratio.

Support Substrate With reference to FIGS. 2A and 2B, a method of manufacturing a support substrate according to the embodiment of the present disclosure will be described. 2A and 2B are process cross-sectional views showing a method of manufacturing the support substrate 200 according to the embodiment of the present disclosure.

First, prepare the base 10 as shown in FIG. 2A. The base 10 is a carrier substrate for a process, and its thickness can be, for example, about 0.3 to 0.7 mm. The base 10 is typically made of glass. The base 10 is required to transmit the peeling light to be irradiated in a later step.

Next, as shown in FIG. 2B, the release layer 12 is formed on the base 10. The release layer 12 is formed of an alloy of aluminum and silicon. The weight ratio of silicon contained in the alloy is 4% or more and 20% or less. By containing silicon in such a weight ratio, the coefficient of linear expansion of the release layer 12 is lower than the coefficient of linear expansion of pure aluminum (23.6 ppm / K). Further, as described above, by adjusting the silicon content of the aluminum alloy and the deposition conditions, the absolute value of the internal stress of the release layer 12 is reduced to 10 MPa or less, and the linear expansion coefficient of the release layer 12 is reduced to the resin film 30. It can be put in the range of 30% or more and 500% or less of the coefficient of linear expansion of. When the weight ratio of silicon contained in the alloy is 10% or more and 15% or less, the coefficient of linear expansion is the smallest among the alloys of aluminum and silicon, and the heat resistance and abrasion resistance are excellent. Therefore, there is an advantage that the base 10 on which the release layer 12 is formed can be easily reused. Thermal distortion may occur at the interface between the resin film 30 and the release layer 12 due to the release layer 12 that absorbs the release light (ultraviolet laser light) and generates heat. If there is a large difference in the value of the coefficient of linear expansion between the resin film 30 and the release layer 12 (for example, a difference of 10 times or more), a large distortion occurs in the resin film 30, and the resin film 30 and the functional layer region There is also a possibility of causing cracks in the lower barrier film inserted between the 20 and the 20. From this point of view, the coefficient of linear expansion of the release layer 12 does not necessarily have to be close to the coefficient of linear expansion of the base 10. It can be said that the alloy of aluminum and silicon has a coefficient of linear expansion in an appropriate range for both the resin film 30 and the base 10.

In the present embodiment, the linear expansion coefficients (room temperature) of the TFT layer 20A, the resin film 30, the release layer 12, and the base 10 are, for example, 2 to 5 ppm / K, several tens of ppm / K, and 19 to 23 ppm / K, respectively. , And 3-5 ppm / K. When a lower gas barrier film, which will be described later, is provided between the TFT layer 20A and the resin film 30, the coefficient of linear expansion of the lower gas barrier film is, for example, about 2 to 5 ppm / K. The coefficient of linear expansion of transparent polyimide, which is the material of the resin film 30, is about 25 ppm / K, and the coefficient of linear expansion of polyethylene terephthalate (PET) is about 60 ppm / K. According to the study of the present inventor, the coefficient of linear expansion of the release layer is between the coefficient of linear expansion of the base 10 and the coefficient of linear expansion of the resin film 30, or equal to or greater than the coefficient of linear expansion of the base 10, and the coefficient of linear expansion of the resin film 30. It is desirable that the coefficient is 5 times or less (for example, 15 to 23 ppm / K, in a more specific example, 15 to 20 ppm / K).

The thickness of the release layer 12 can be 100 nm or more and 5000 nm or less. A typical example of the method for forming the release layer 12 is a sputtering method, but the release layer 12 can be formed by a plating method. By using the plating method, a release layer 12 having a thickness on the order of μm can be realized. Further, since the main component of the alloy constituting the release layer 12 is aluminum, the thermal conductivity of the alloy is sufficiently high, and even a thick film of about several μm can be peeled off.

When the release layer 12 is formed by the sputtering method, an alloy is deposited on the base 10 by sputtering an aluminum target containing silicon.

The resin film 30 may be peeled from the release layer 12 by a laser lift-off step described later, and then the release layer 12 may be removed from the base 10 and recovered.

The main component of the aluminum alloy used for the release layer 12 is aluminum having a low melting point. However, since this material has a large specific heat and latent heat of melting and good heat conduction, local heating is unlikely to occur. In other words, although the aluminum alloy is a material having a lower melting point than the refractory metal, the release layer 12 does not melt when the release layer 12 is irradiated with strong peeling light. Further, when heat is generated by irradiation with peeling light, even if the spatial distribution of the peeling light intensity becomes non-uniform, heat is easily conducted to the surroundings, so that peeling failure is unlikely to occur. More specifically, when dust adheres to the back surface of the base 10 or scratches are formed, when the release light is incident on the release layer 12 from the back surface of the base 10, it is caused by the shadow or scratches of the dust. Diffraction / reflection or the like may cause a local decrease in the intensity of separated light on the release layer 12. When the resin film 30 is peeled by utilizing the heat generated by the photochemical reaction, if such a local shortage of the peeling light intensity occurs, the peeling is not realized at that position, and a problem of poor peeling occurs. However, since the release layer 12 in the present embodiment absorbs the peeling light to generate heat and transfer heat, the above problem due to the local shortage of the peeling light intensity can be avoided.

Hereinafter, the configuration and manufacturing method of the laminated structure 100 will be described in more detail.

First, refer to FIG. 3A. FIG. 3A is a cross-sectional view showing a support substrate 200 having a resin film 30 formed on its surface.

The resin film 30 in the present embodiment is, for example, a polyimide film having a thickness of 5 μm or more and 20 μm or less, for example, about 10 μm. The polyimide film can be formed from a precursor polyamic acid or a polyimide solution. A film of polyamic acid may be formed on the surface of the release layer 12 of the support substrate 200 and then thermally imidized, or a film may be formed on the surface of the release layer 12 from a polyimide solution in which polyimide is melted or dissolved in an organic solvent. You may. The polyimide solution can be obtained by dissolving a known polyimide in an arbitrary organic solvent. A polyimide film can be formed by applying a polyimide solution to the surface of the base 10 and then drying it.

In the case of a bottom emission type flexible display, the polyimide film preferably realizes high transmittance in the entire visible light region. The transparency of the polyimide film can be expressed by, for example, the total light transmittance according to JIS K7105-1981. The total light transmittance can be set to 80% or more, or 85% or more. On the other hand, in the case of a top emission type flexible display, it is not affected by the transmittance.

The resin film 30 may be a film formed of a synthetic resin other than polyimide. However, in the embodiment of the present disclosure, since heat treatment at, for example, 350 ° C. or higher is performed in the step of forming the thin film transistor, the resin film 30 is formed from a material that is not deteriorated by this heat treatment.

The resin film 30 may be a laminate of a plurality of synthetic resin films. In one aspect of the present embodiment, when the structure of the flexible display is peeled from the base 10, LLO is performed to irradiate the resin film 30 with an ultraviolet laser beam (wavelength: 300 to 360 nm) transmitted through the base 10. Since the release layer 12 that absorbs ultraviolet rays and generates heat is arranged between the base 10 and the resin film 30, a part of the resin film 30 is formed at the interface between the release layer 12 and the resin film 30 by irradiation with ultraviolet laser light. The (layered portion) is vaporized and the resin film 30 can be easily peeled off from the release layer 12, that is, the support substrate 200. The presence of the release layer 12 also has the effect of suppressing the formation of ash.

Since the release layer 12 in the embodiment of the present disclosure has the property of a metal containing aluminum as a main component, the transmittance of the release layer 12 to ultraviolet rays is extremely low. Therefore, the release layer 12 functions as an ultraviolet shielding layer in the lift-off process. As a result, it is avoided or suppressed that strong ultraviolet laser light is incident on the functional layer region 20 from the base 10 and deteriorates the characteristics of the TFT layer 20A and the light emitting element layer 20B.

In general, it has been considered that even a highly transparent resin film 30 absorbs almost all ultraviolet rays. However, since the resin film 30 used in the flexible light emitting device is an extremely thin layer, if the release layer 12 formed of the metal material is not present, the ultraviolet laser beam is incident on the functional layer region 20. Ultraviolet rays may deteriorate not only the characteristics of the TFT layer 20A and the light emitting element layer 20B but also the sealing performance of the organic film and the inorganic film constituting the sealing structure. Furthermore, since the currently widely used resin film 30 is formed of a yellow-brown or brown-brown polyimide material, it is not recognized that the transmission of ultraviolet rays can cause deterioration of the characteristics of the functional layer region. This is because such a polyimide material having low transparency strongly absorbs ultraviolet rays. However, according to the study by the present inventor, it has been found that even if the resin film 30 has low transparency, ultraviolet rays can reach the functional layer region 20 if the thickness is only about 5 to 20 μm, for example. Therefore, the method according to the embodiment of the present disclosure includes not only a light emitting device provided with a resin film (flexible substrate) formed of a material having high transparency and easily transmitting ultraviolet rays, but also a thin resin film 30 (thickness) having low transparency. It is suitably used for manufacturing a light emitting device having (about 5 to 20 μm).

Note that polyimide and PET with high transparency that transmit ultraviolet rays have lower heat resistance than polyimide with low transparency. However, according to the study of the present inventor, as described above, the release layer 12 formed of an alloy made of aluminum and silicon has a large specific heat / molten latent heat and good heat conduction, so that heat generated by ultraviolet irradiation causes the release layer 12 to generate heat. It was found that heat is quickly transferred through the film, and even a resin film having low heat resistance such as highly transparent polyimide and PET can be satisfactorily peeled off without damaging it. In other words, it was found that the release layer 12 does not have to be formed of a refractory metal, and LLO is possible even if it is formed of a non-melting point metal material such as aluminum as a main component.

Forming the release layer 12 can lead to an increase in manufacturing cost, but unlike refractory metals, aluminum alloys can be easily dissolved by a chemical solution, so that they can be recovered and recycled. Therefore, even if the release layer is adopted, the increase in manufacturing cost can be suppressed to a low level.

<Polishing process>
When a polishing target (target) such as particles or convex portions exists on the surface 30x of the resin film 30, the target may be polished and flattened by a polishing device. Foreign matter such as particles can be detected, for example, by processing an image acquired by an image sensor. After the polishing treatment, the surface 30x of the resin film 30 may be flattened. The flattening treatment includes a step of forming a film (flattening film) for improving flatness on the surface 30x of the resin film 30. The flattening film does not have to be made of resin.

<Lower gas barrier membrane>
Next, a gas barrier film (not shown) may be formed on the resin film 30. The gas barrier membrane can have various structures. Examples of gas barrier membranes are films such as silicon oxide films or silicon nitride films. Another example of a gas barrier membrane may be a multilayer membrane in which an organic material layer and an inorganic material layer are laminated. This gas barrier membrane may be referred to as a "lower gas barrier membrane" in order to distinguish it from the gas barrier membrane described later that covers the functional layer region 20. Further, the gas barrier membrane covering the functional layer region 20 can be called an "upper layer gas barrier membrane". The underlayer gas barrier membrane can be formed from, for example, Si ₃ N ₄ . The coefficient of linear expansion of Si ₃ N ₄ is about 3 ppm / K. According to an embodiment of the present disclosure, since the coefficient of thermal expansion of the release layer 12 is between the coefficient of linear expansion of the base 10 and the coefficient of linear expansion of the resin film 30, the lower gas barrier layer formed from Si ₃ N ₄ The problem of cracking can be avoided.

<Functional layer area>
Next, a step of forming the functional layer region 20 including the TFT layer 20A and the light emitting element layer 20B, and the upper gas barrier film 40 will be described.

First, as shown in FIG. 3B, a plurality of functional layer regions 20 are formed on the base 10. The release layer 12 and the resin film 30 fixed to the base 10 are located between the base 10 and the functional layer region 20.

More specifically, the functional layer region 20 includes a TFT layer 20A located in the lower layer and a light emitting element layer 20B located in the upper layer. The TFT layer 20A and the light emitting element layer 20B are sequentially formed by a known method. The TFT layer 20A includes a circuit of a TFT array that realizes an active matrix. The light emitting element layer 20B includes an array of light emitting elements (OLED elements and / or micro LED elements), each of which can be driven independently. The chip size of the micro LED element is smaller than, for example, 100 μm × 100 μm. The micro LED element can be formed from different inorganic semiconductor materials depending on the color or wavelength of the emitted light. The same semiconductor chip may include a plurality of semiconductor laminated structures having different compositions, and different R, G, and B lights may be emitted from the respective semiconductor laminated structures.

The thickness of the TFT layer 20A may be, for example, 4 μm, and the thickness of the light emitting element layer 20B including the OLED element may be, for example, 10 μm or more.

FIG. 4 is a basic equivalent circuit diagram of sub-pixels in an organic EL (Electro Luminescence) display which is an example of a light emitting device. One pixel of the display may be composed of sub-pixels of different colors such as R (red), G (green), B (blue). The example shown in FIG. 4 has a selection TFT element Tr1, a driving TFT element Tr2, a holding capacity CH, and a light emitting element EL. The selection TFT element Tr1 is connected to the data line DL and the selection line SL. The data line DL is a wiring that carries a data signal that defines an image to be displayed. The data line DL is electrically connected to the gate of the driving TFT element Tr2 via the selection TFT element Tr1. The selection line SL is a wiring that carries a signal for controlling on / off of the selection TFT element Tr1. The driving TFT element Tr2 controls the conduction state between the power line PL and the light emitting element EL. When the driving TFT element Tr2 is turned on, a current flows from the power line PL to the ground line GL via the light emitting element EL. This current causes the light emitting element EL to emit light. Even if the selection TFT element Tr1 is turned off, the driving TFT element Tr2 is maintained in the ON state due to the holding capacitance CH.

The TFT layer 20A includes a selection TFT element Tr1, a driving TFT element Tr2, a data line DL, a selection line SL, and the like. The light emitting element layer 20B includes a light emitting element EL. Before the light emitting element layer 20B is formed, the upper surface of the TFT layer 20A is flattened by an interlayer insulating film covering the TFT array and various wirings. A structure that supports the light emitting element layer 20B and realizes active matrix driving of the light emitting element layer 20B is referred to as a "backplane".

A part of the circuit element and the wiring shown in FIG. 4 may be included in either the TFT layer 20A or the light emitting element layer 20B. Further, the wiring shown in FIG. 4 is connected to a driver circuit (not shown).

In the embodiment of the present disclosure, the specific configurations of the TFT layer 20A and the light emitting element layer 20B can be various. These configurations do not limit the content of this disclosure. The structure of the TFT element included in the TFT layer 20A may be a bottom gate type or a top gate type. Further, the light emission of the light emitting element included in the light emitting element layer 20B may be a bottom emission type or a top emission type. The specific configuration of the light emitting element is also arbitrary.

The material of the semiconductor layer constituting the TFT element includes, for example, crystalline silicon, amorphous silicon, and an oxide semiconductor. In the embodiment of the present disclosure, in order to improve the performance of the TFT element, a part of the steps of forming the TFT layer 20A includes a heat treatment step of 350 ° C. or higher.

<Upper gas barrier membrane>
After forming the functional layer region 20, as shown in FIG. 3C, the entire functional layer region 20 is covered with the gas barrier film (upper layer gas barrier film) 40. A typical example of the upper gas barrier film 40 is a multilayer film in which an inorganic material layer and an organic material layer are laminated. Elements such as an adhesive film, another functional layer constituting the touch screen, and a polarizing film may be arranged between the upper gas barrier film 40 and the functional layer region 20 or further above the upper gas barrier film 40. .. The upper gas barrier film 40 can be formed by a thin film encapsulation (TFE) technique. From the viewpoint of sealing reliability, the WVTR (Water Vapor Transmission Rate) of the thin film sealing structure is typically required to be 1 × 10 ^-4 g / m ² / day or less. According to the embodiments of the present disclosure, this criterion is achieved. The thickness of the upper gas barrier film 40 is, for example, 1.5 μm or less.

FIG. 5 is a perspective view schematically showing the upper surface side of the laminated structure 100 at the stage where the upper gas barrier film 40 is formed. One laminated structure 100 includes a plurality of light emitting devices 1000 supported by the base 10. In the example shown in FIG. 5, one laminated structure 100 includes more functional layer regions 20 than in the example shown in FIG. 1A. As described above, the number of functional layer regions 20 supported by one base 10 is arbitrary.

<Protective sheet>
Next, refer to FIG. 3D. As shown in FIG. 3D, the protective sheet 50 is attached to the upper surface of the laminated structure 100. The protective sheet 50 can be formed from a material such as polyethylene terephthalate (PET) or polyvinyl chloride (PVC). As described above, a typical example of the protective sheet 50 has a laminated structure having a coating layer of a release agent on the surface. The thickness of the protective sheet 50 can be, for example, 50 μm or more and 150 μm or less.

After preparing the laminated structure 100 thus produced, the production method according to the present disclosure can be executed using the above-mentioned production apparatus (peeling apparatus 220).

The laminated structure 100 that can be used in the manufacturing method of the present disclosure is not limited to the examples shown in FIGS. 1A and 1B. The protective sheet 50 may cover the entire resin film 30 and may extend outward from the resin film 30. Alternatively, the protective sheet 50 may cover the entire resin film 30 and may extend outward from the base 10. As will be described later, after the base 10 is isolated from the laminated structure 100, the laminated structure 100 becomes a flexible thin sheet-like structure having no rigidity. The protective sheet 50 impacts the functional layer region 20 when the functional layer region 20 collides with or comes into contact with an external device or instrument in the step of peeling the base 10 and the step after the peeling. It plays a role of protecting from friction. Since the protective sheet 50 is finally peeled off from the laminated structure 100, a typical example of the protective sheet 50 has a laminated structure having an adhesive layer (coating layer of a release agent) having a relatively small adhesive force on the surface. doing. A more detailed description of the laminated structure 100 will be described later.

<Division of light emitting device>
In the method for manufacturing a flexible light emitting device of the present embodiment, after executing the step of preparing the laminated structure 100, the step of dividing each of the intermediate region 30i of the resin film 30 and the plurality of flexible substrate regions 30d is performed. The step of performing the division does not have to be performed before the LLO step, and may be performed after the LLO step.

The division can be performed by cutting the central part of the adjacent light emitting device with a laser beam or a dicing saw. In the present embodiment, the portion of the laminated structure other than the base 10 is cut, and the base 10 is not cut. However, the base 10 may be cut and divided into a partially laminated structure including individual light emitting devices and a base portion supporting each light emitting device.

Hereinafter, the process of cutting the laminated structure other than the base 10 by irradiating the laser beam will be described. The irradiation position of the laser beam for cutting is along the outer circumference of each flexible substrate region 30d.

6A and 6B are cross-sectional views and plan views schematically showing positions for dividing the intermediate region 30i of the resin film 30 and each of the plurality of flexible substrate regions 30d, respectively. The irradiation position of the laser beam for cutting is along the outer circumference of each flexible substrate region 30d. In FIGS. 6A and 6B, the irradiation position (cutting position) CT indicated by the arrow or the broken line is irradiated with a laser beam for cutting, and the portion of the laminated structure 100 other than the base 10 is subjected to a plurality of light emitting devices 1000 and others. Cut into unnecessary parts. By cutting, a gap of several tens of μm to several hundreds of μm is formed between each light emitting device 1000 and its surroundings. As described above, such cutting can be performed by a dicing saw instead of irradiating the laser beam. Even after cutting, the light emitting device (for example, the display panel) 1000 and other unnecessary parts are fixed to the base 10.

As shown in FIG. 6B, the planar layout of the "unnecessary portion" in the laminated structure 100 is consistent with the planar layout of the intermediate region 30i of the resin film 30. In the illustrated example, this "unwanted portion" is a single continuous sheet-like structure with an opening. However, the embodiments of the present disclosure are not limited to this example. The irradiation position CT of the cutting laser beam may be set so as to divide the "unnecessary portion" into a plurality of portions. The sheet-like structure which is an "unnecessary portion" includes not only the intermediate region 30i of the resin film 30 but also the cut portion of the laminate (for example, the gas barrier film 40 and the protective sheet 50) existing on the intermediate region 30i. Includes.

When cutting with a laser beam, the wavelength of the laser beam may be in any region of infrared, visible light, and ultraviolet. From the viewpoint of reducing the influence of cutting over the base 10, a laser beam having a wavelength in the green to ultraviolet region is desirable. For example, according to the Nd: YAG laser apparatus, cutting can be performed using a second harmonic (wavelength 532 nm) or a third harmonic (wavelength 343 nm or 355 nm). In that case, if the laser output is adjusted to 1 to 3 watts and scanning is performed at a speed of about 500 mm per second, the laminate supported by the base 10 can be used as a light emitting device and an unnecessary part without damaging the base 10. It can be cut (divided).

According to the embodiment of the present disclosure, the timing of performing the above cutting is earlier than that of the prior art. Since the cutting is performed with the resin film 30 fixed to the base 10, even if the distance between the adjacent light emitting devices 1000 is narrow, the cutting can be aligned with high accuracy and accuracy. Therefore, the interval between the adjacent light emitting devices 1000 can be shortened, and the wasteful portion that is finally unnecessary can be reduced.

<Exfoliation light irradiation>
FIG. 7A is a diagram schematically showing a state immediately before the stage 212 supports the laminated structure 100 in a manufacturing apparatus (peeling apparatus) (not shown). The stage 212 in this embodiment is an adsorption stage having a large number of holes for adsorption on the surface. The configuration of the suction stage is not limited to this example, and may include an electrostatic chuck or other fixing device that supports the laminated structure. The laminated structure 100 is arranged so that the second surface 100b of the laminated structure 100 faces the surface 212S of the stage 212, and is in close contact with the stage 212.

FIG. 7B is a diagram schematically showing a state in which the stage 212 supports the laminated structure 100. The arrangement relationship between the stage 212 and the laminated structure 100 is not limited to the illustrated example. For example, the laminated structure 100 may be turned upside down and the stage 212 may be located below the laminated structure 100.

In the example shown in FIG. 7B, the laminated structure 100 is in contact with the surface 212S of the stage 212, and the stage 212 is adsorbing the laminated structure 100.

Next, as shown in FIG. 7C, the release layer 12 located between the plurality of flexible substrate regions 30d of the resin film 30 and the base 10 is irradiated with the release light 216. FIG. 7C is a diagram schematically showing a state in which the release layer 12 is irradiated from the side of the base 10 by the peeling light 216 formed in a line shape extending in the direction perpendicular to the paper surface of the figure. The release layer 12 absorbs the peeling light 216 and is heated in a short time. A part of the resin film 30 is vaporized or decomposed (disappeared) by heat from the release layer 12 at the interface between the release layer 12 and the resin film 30. By scanning the release layer 12 with the release light 216, the degree of adhesion of the resin film 30 to the release layer 12, in other words, the support substrate 200 is reduced. The wavelength of the delamination light 216 is typically in the ultraviolet region. The light absorption rate of the base 10 is, for example, about 10% in the region where the wavelength is 343 to 355 nm, but can increase to 30 to 60% in the region of 308 nm.

Hereinafter, the irradiation of the peeling light in the present embodiment will be described in detail.

<Peeling light irradiation device 1>
The peeling device in the present embodiment includes a line beam light source that emits peeling light 216. The line beam light source includes a laser device and an optical system that forms a laser beam emitted from the laser device into a line beam shape.

FIG. 8A is a perspective view schematically showing how the laminated structure 100 is irradiated with the line beam (peeling light 216) emitted from the line beam light source 214 of the peeling device 220. For the sake of clarity, the stage 212, the laminated structure 100, and the line beam light source 214 are shown apart from each other in the Z-axis direction in the figure. When the peeling light 216 is irradiated, the second surface 100b of the laminated structure 100 is in contact with the stage 212.

FIG. 8B schematically shows the position of the stage 212 when the peeling light 216 is irradiated. Although not shown in FIG. 8B, the laminated structure 100 is supported by the stage 212.

Examples of laser devices that emit the separation light 216 include gas laser devices such as excimer lasers, solid-state laser devices such as YAG lasers, semiconductor laser devices, and other laser devices. According to the XeCl excimer laser apparatus, a laser beam having a wavelength of 308 nm can be obtained. When neodymium (Nd) -doped yttrium / vanadium tetroxide (YVO ₄ ) or itterbium (Yb) -doped YVO ₄ is used as the laser oscillation medium, the laser beam emitted from the laser oscillation medium (basic). Since the wavelength of the wave) is about 1000 nm, it can be used after being converted into a laser beam (third harmonic) having a wavelength of 340 to 360 nm by a wavelength conversion element.

From the viewpoint of suppressing the formation of ash, it is more effective to use the laser beam having a wavelength of 308 nm by the excimer laser device than the laser beam having a wavelength of 340 to 360 nm. In addition, the presence of the release layer 12 exerts a remarkable effect on suppressing ash formation.

Irradiation of the peeling light 216 can be performed with an energy irradiation density of, for example, 50 to 400 mJ / cm ² . By using a release layer made of an alloy of aluminum and silicon having good thermal conductivity, the lower limit of the energy irradiation density can be greatly widened. The line beam-shaped peeling light 216 has a size that crosses the base 10, that is, a line length that exceeds the length of one side of the base (major axis dimension, Y-axis direction size in FIG. 8B). The line length can be, for example, 750 mm or more. On the other hand, the line width of the peeling light 216 (short axis dimension, X-axis direction size in FIG. 8B) can be, for example, about 0.2 mm. These dimensions are the size of the irradiation region at the interface between the resin film 30 and the base 10. The separation light 216 can be irradiated as a pulse or a continuous wave. The pulsed irradiation can be performed at a frequency of, for example, about 200 times per second.

The irradiation position of the peeling light 216 moves relative to the base 10, and the scanning of the peeling light 216 is executed. In the peeling device 220, the light source 214 and the optical device (not shown) that emit the peeling light are fixed, and the laminated structure 100 may move or vice versa. In this embodiment, the peeling light 216 is irradiated while the stage 212 moves from the position shown in FIG. 8B to the position shown in FIG. 8C. That is, the movement of the stage 212 along the X-axis direction executes scanning of the peeling light 216.

<Peeling light irradiation device 2>
The light source included in the peeling light irradiation device in the above embodiment is a laser light source, but the peeling light irradiation device of the present disclosure is not limited to this example. The exfoliated light may be emitted from a non-coherent light source instead of a coherent light source such as a laser light source. Hereinafter, an example of irradiating the interface between the resin film and the glass base with the peeling light emitted from the ultraviolet lamp will be described.

FIG. 9A is a cross-sectional view schematically showing a configuration example of a surface light source 215 that emits separation light 216. FIG. 9B is a top view showing a configuration example of the surface light source 215.

The surface light source 215 shown in the figure includes a plurality of ultraviolet lamps 380 arranged in a region facing the laminated structure 100, and a reflector 390 that reflects the ultraviolet light emitted from each ultraviolet lamp 380. The ultraviolet lamp 380 can be, for example, a high-pressure mercury lamp that emits i-rays having a wavelength of 365 nm. The reflector 390 in the illustrated example can reflect the ultraviolet light radiated from the ultraviolet lamp 380 to the surroundings to make it substantially parallel light. When the reflector 390 is formed of a cold mirror, it is possible to prevent an infrared component contained in the light emitted from the high-pressure mercury lamp from incident on the laminated structure 100. An infrared cut filter may be arranged between the ultraviolet lamp 380 and the laminated structure 100. By reducing or cutting the infrared component that can be contained in the peeling light 216, it is possible to suppress or prevent the temperature rise of the laminated structure 100 due to infrared irradiation.

The irradiation energy of the peeling light required for peeling the resin film 30 is, for example, in the range of 100 mJ / cm ² or more and 300 mJ / cm ² or less. A light source (non-coherent light source) such as the ultraviolet lamp 380 generally has a smaller irradiation intensity per unit area than the above-mentioned laser light source. Therefore, in order to achieve sufficient irradiation energy, the separation light irradiation time may be longer than when a laser light source is used.

Since the surface light source 215 shown in FIGS. 9A and 9B can form the separation light 216 spreading in a plane shape, it is easy to lengthen the irradiation time at each position as compared with the case of scanning the line beam. ..

In the example of FIG. 9A, the peeling light 216 parallelized by the reflector 390 is formed, but the embodiment of the present disclosure is not limited to this example. The light emitted from each ultraviolet lamp 380 may be focused in a line having a width of about 1 to 3 mm by using a reflector 390 and a lens (not shown). When the laminated structure 100 is irradiated with such striped peeling light 216, the entire surface of the laminated structure 100 is irradiated with the peeling light 216 by shifting the relative position of the surface light source 215 with respect to the laminated structure 100. be able to.

When the irradiation intensity of the ultraviolet light emitted from the ultraviolet lamp 380 is high, it is possible to irradiate the entire surface of the laminated structure 100 with the peeling light 216 by scanning with one or several ultraviolet lamps 380. Even if the irradiation intensity of the ultraviolet light emitted from the ultraviolet lamp 380 is not high, if the scanning speed is reduced, the entire surface of the laminated structure 100 can be exposed to the peeling light 216 by scanning one or several ultraviolet lamps 380. It is possible to irradiate.

<Peeling light irradiation device 3>
Hereinafter, an example of irradiating the interface between the resin film and the glass base with the peeling light emitted from a non-coherent light source having a plurality of light emitting diode elements will be described.

As a light source that emits separation light, a plurality of light emitting diode (UV-LED) elements that emit ultraviolet light can be used. Each of such light emitting diode elements has a size of, for example, 3.5 mm in length × 3.5 mm in width × 1.2 mm in thickness. A plurality of light emitting diode elements may be used in one row or in a plurality of rows.

FIG. 10 is a cross-sectional view schematically showing a surface light source 215 including a plurality of light emitting diode elements 400 arranged two-dimensionally. The light emitted from the individual light emitting diode elements 400 spreads around the Z-axis direction. This light shows the distribution (directivity) of the relative radiant intensity depending on the radiation angle θ which is the inclination from the Z axis. In one example, the relative radiant intensity of the light emitting diode element can be about 75% at θ = 45 ° and about 50% at θ = 65 °. The directivity of the light emitting diode element can be adjusted by arranging a lens and / or a reflector.

According to a commercially available light emitting diode element, for example, ultraviolet light having a wavelength of 365 nm can be emitted at an output of 1450 milliwatts under a driving condition of a voltage of 3.85 volts and a current of 1000 milliamperes.

FIG. 11 is a cross-sectional view showing a surface light source 215 in which the in-plane number density of the light emitting diode element 400 is increased as compared with the example shown in FIG. The higher the in-plane number density of the light emitting diode element 400, the higher the irradiation intensity.

FIG. 12 is a diagram showing an array of light emitting diode elements 400 arranged in rows and columns. The spacing (arrangement pitch) P of the adjacent light emitting diode elements 400 is selected so that the irradiation intensity exceeds the level required for peeling at the entire interface between the resin film and the glass base.

<Peeling light irradiation device 4>
The light emitting intensity of the light emitting diode element is controlled by adjusting the magnitude of the drive current. Therefore, in a state where a plurality of light emitting diode elements are arranged one-dimensionally or two-dimensionally, the irradiation intensity of the separation light is modulated temporally and / or spatially by modulating the drive current flowing through each light emitting diode element. You can also do it.

The arrangement pitch of the light emitting diode elements is, for example, in the range of 3 mm or more and 10 mm or less. The light emitted from the light emitting diode element is incoherent (non-coherent) light, unlike laser light. The wavelength of the light emitted from the light emitting diode element is, for example, in the range of 300 nm or more and 380 nm or less.

An example of a line beam light source in which a plurality of light emitting diode elements are arranged will be described with reference to FIGS. 13A, 13B, and 13C.

FIG. 13A schematically shows the upper surface of a line beam light source 214 including a plurality of light emitting diode elements 400 arranged in the Y-axis direction. FIG. 13B is a sectional view taken along line BB of the line beam light source 214 shown in FIG. 13A. FIG. 13B also shows the laminated structure 100. FIG. 13C is a diagram showing the moving direction of the line beam light source 214 with respect to the laminated structure 100.

In this example, the ultraviolet light emitted from the light emitting diode element 400 passes through the cylindrical lens 410 and the glass of the laminated structure 100 in order to increase the irradiation energy per unit area (irradiation intensity: unit is joule / cm ² ). It is incident on the base 10. Since the ultraviolet light is focused in the X-axis direction, the width (X-axis direction size) of the irradiation region at the interface (peeling surface) where peeling occurs can be narrowed to, for example, about 0.2 mm or less. Since the cylindrical lens 410 does not focus in the X-axis direction, the size of the irradiation region in the Y-axis direction is not shortened.

In order to increase the irradiation intensity of the peeling light, the arrangement pitch of the light emitting diode elements 400 may be reduced to increase the number density of the light emitting diode elements 400. For example, when the size of each light emitting diode element 400 has the above-mentioned size, the number of light emitting diodes is tens or 100 or more at intervals of 3.5 mm to 10 mm (arrangement pitch: distance between centers of adjacent light sources). The elements 400 may be arranged. When a smaller light emitting diode element 400 is used, it can be arranged at intervals of 2.0 mm to 10 mm, for example. The arrangement pitch of the light emitting diode element 400 is preferably 5 mm or less.

By moving the line beam light source 214 with respect to the laminated structure 100 as shown in FIG. 13C, the entire surface of the laminated structure 100 can be irradiated with the peeling light.

In order to increase the irradiation intensity of the line beam light source 214, the light emitting diode elements 400 may be arranged in a plurality of rows.

FIG. 14A schematically shows the upper surface of a line beam light source 214 including a plurality of rows of light emitting diode elements 400 arranged in the Y-axis direction. FIG. 14B is a sectional view taken along line BB of the line beam light source 214 shown in FIG. 14A. FIG. 14B also shows the laminated structure 100. FIG. 14C is a diagram showing the moving direction of the line beam light source 214 with respect to the laminated structure 100.

The line beam light source 214 of this example each includes five rows of light emitting diode elements 400 extending in the Y-axis direction. The positions of the five rows of light emitting diode elements 400 in the Y-axis direction are different from each other. When the array pitch is P, the positions of the light emitting diode rows are shifted by P / 5 in the Y-axis direction between the adjacent rows. By moving the line beam light source 214 with respect to the laminated structure 100 as shown in FIG. 14C, the entire surface of the laminated structure 100 can be irradiated with the separation light.

The peeling light may be irradiated in a state where a plurality of light sources are stationary with respect to the laminated structure 100.

FIG. 15 is a top view schematically showing an example of a surface light source 215 in which a large number of light emitting diode elements 400 are arranged in a matrix. The in-plane to be peeled may be divided into a plurality of regions, and each region may be irradiated with a flash of peeling light in the same manner as in the sequential exposure with a stepper.

When the laminated structure 100 and the surface light source 215 are both stationary and the peeling light is irradiated, a precise driving device for optical scanning becomes unnecessary. Further, when the peeling light is irradiated to the fixed line beam light source while moving the laminated structure 100 (FIGS. 13A-13C or 14A-14C), the laminated structure 100 is laminated for movement. An area with twice the area of the structure 100 is required. However, if the surface light source 215 is used, an extra area required for moving the laminated structure 100 becomes unnecessary, and there is an advantage that the installation area of the device is halved.

By using the light emitting diode element in this way, it becomes possible to execute the detached light irradiation using a large number of light sources at a lower cost than using a relatively expensive semiconductor laser element. Further, since it is easy to lengthen the time for emitting the peeling light from each light emitting diode element, even if the light output of each light emitting diode element is small, the irradiation energy required for peeling can be adjusted by adjusting the irradiation time. Can be achieved. Furthermore, since laser light is not used, it is advantageous in terms of safety for the human eye (eye safety), and easier device design and operation becomes possible.

<Lift off>
FIG. 16A shows a state in which the laminated structure 100 is in contact with the stage 212 after irradiation with the peeling light. While maintaining this state, the distance from the stage 212 to the base 10 is increased. At this time, the stage 212 in the present embodiment is adsorbing the light emitting device portion of the laminated structure 100.

A drive device (not shown) holds the base 10 and moves the entire base 10 in the direction of the arrow to perform peeling (lift-off). The base 10 can move together with the suction stage in a state of being sucked by a suction stage (not shown). The direction of movement of the base 10 does not have to be perpendicular to the first surface 100a of the laminated structure 100, and may be inclined. The movement of the base 10 does not have to be a linear motion, but may be a rotary motion. Further, the base 10 may be fixed by a holding device (not shown) or another stage, and the stage 212 may move to the upper side of the drawing.

FIG. 16B is a cross-sectional view showing a first portion 110 and a second portion 120 of the laminated structure 100 thus separated. The first portion 110 of the laminated structure 100 includes a plurality of light emitting devices 1000 in contact with the stage 212. Each light emitting device 1000 has a functional layer region 20 and a plurality of flexible substrate regions 30d of the resin film 30. On the other hand, the second portion 120 of the laminated structure 100 has a base 10 and a release layer 12.

Since the individual light emitting devices 1000 supported by the stage 212 are disconnected from each other, they can be easily removed from the stage 212 simultaneously or sequentially.

In the above embodiment, each light emitting device 1000 is cut and separated before the LLO step, but each light emitting device 1000 may be cut and separated after the LLO step. Further, the cutting separation of each light emitting device 1000 may include dividing the base 10 into corresponding portions.

According to the embodiment of the present disclosure, when a flexible film formed of polyimide and PET having high transparency that transmits ultraviolet rays is used, or a flexible film having low transparency but thin (thickness 5 to 20 μm) capable of transmitting ultraviolet rays. Even when the above is used, deterioration of the characteristics of the functional layer region and deterioration of the performance of the gas barrier layer due to ultraviolet rays can be suppressed. Further, unlike the refractory metal, the aluminum alloy can be easily recovered and recycled, so that the increase in manufacturing cost due to the adoption of the release layer can be suppressed to a low level.

An embodiment of the present invention provides a method for manufacturing a new flexible light emitting device. Flexible light emitting devices can be widely applied to smartphones, tablet terminals, in-vehicle displays, and small to medium to large television devices. The flexible light emitting device can also be used as a lighting device.

10 ... base, 12 ... release layer, 20 ... functional layer region, 20A ... TFT layer, 20B ... light emitting element layer, 30 ... resin film, 30d ... resin film Flexible substrate region, 30i ... Intermediate region of resin film, 40 ... Gas barrier film, 50 ... Protective sheet, 100 ... Laminated structure, 212 ... Stage, 1000 ... Light emitting device

Claims

Between the base, a functional layer region including a TFT layer and a light emitting element layer, a flexible film located between the base and the functional layer region and supporting the functional layer region, and between the flexible film and the base. A step of preparing a laminated structure including a release layer located at and fixed to the base, and irradiating the release layer with ultraviolet peeling light transmitted through the base to peel the flexible film from the release layer. And the process to do
Including
A method for manufacturing a flexible light emitting device, wherein the release layer is formed of an alloy of aluminum and silicon.
The manufacturing method according to claim 1, wherein the ultraviolet exfoliation light is non-coherent light.
The light emitting element layer includes a plurality of arranged micro LEDs.
The manufacturing method according to claim 1, wherein the ultraviolet exfoliation light is laser light.
The production method according to any one of claims 1 to 3, wherein the weight ratio of silicon contained in the alloy is 4% or more and 20% or less.
The manufacturing method according to any one of claims 1 to 4, wherein the linear expansion coefficient of the release layer is 30% or more and 500% or less of the linear expansion coefficient of the flexible film.
The manufacturing method according to any one of claims 1 to 5, wherein the thickness of the release layer is 100 nm or more and 5000 nm or less.
The production method according to any one of claims 1 to 6, wherein the wavelength of the ultraviolet exfoliation light is 300 nm or more and 360 nm or less.
The manufacturing method according to any one of claims 1 to 7, wherein the thickness of the flexible film is 5 μm or more and 20 μm or less.
The step of preparing the laminated structure is
A step of forming the release layer on the base by sputtering an aluminum target containing silicon, and
The step of forming the flexible film on the release layer and
The production method according to any one of claims 1 to 8, which comprises.
The production method according to any one of claims 1 to 9, further comprising a step of peeling the flexible film from the release layer and then removing and recovering the release layer from the base.
A support substrate for flexible light emitting devices
With a release layer formed from an alloy of aluminum and silicon,
A base formed of a material that transmits ultraviolet rays and supports the release layer,
A support substrate comprising.
The support substrate according to claim 11, further comprising a flexible film that covers the release layer and is formed of the material that transmits ultraviolet rays.
The support substrate according to claim 11 or 12, wherein the weight ratio of silicon contained in the alloy is 4% or more and 20% or less.
The support substrate according to any one of claims 11 to 13, wherein the linear expansion coefficient of the release layer is 30% or more and 500% or less of the linear expansion coefficient of the flexible film.
The support substrate according to any one of claims 11 to 14, wherein the thickness of the release layer is 100 nm or more and 5000 nm or less.