JP2015185479A - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cracks from being caused at an edge of a coating film when a light emitting element is coated with the coating film.SOLUTION: A light emitting device 10 includes a substrate 100, a light emitting element 102 and a coating film 140. The light emitting element 102 is formed on the substrate 100. The coating film 140 is formed over the substrate 100 and coats the light emitting element 102. The substrate 100 includes a region (non-coated region: opening 142) which is not coated with the coating film 140. A corner of an edge of the coating film 140 forms a curve at the boundary between the non-coated region and the coating film 140 when an internal angle of an intersection of extended two straight lines adjacent to each other is 90 degrees or less.

Description

  The present invention relates to a light emitting device.

  In recent years, development of a light emitting device using an organic EL element as a light source has been advanced. Since an organic EL element uses an organic layer as a light emitting layer, a sealing structure is required. Generally, the organic EL element is sealed using a sealing member formed of glass or metal. And the terminal connected to an organic EL element is arrange | positioned outside this sealing member.

  On the other hand, Patent Documents 1 and 2 describe sealing an organic EL element by forming a sealing film using an ALD (Atomic Layer Deposition) method. Patent Document 1 describes that the terminal is exposed from the sealing film by removing the sealing film from above the terminal.

  Specifically, in Patent Document 1, as a method of removing the sealing film from above the terminal, the terminal is covered with a masking tape before the sealing film is formed, and the masking tape is formed after the sealing film is formed. And a method of attaching an adhesive tape to the sealing film on the terminal and then removing the adhesive tape. Patent Document 1 also describes that a sealing film is not formed on the terminal by applying silicone-based oil on the terminal in advance.

  Patent Document 2 describes a method in which a terminal is covered with a polyimide tape before forming a sealing film, and the polyimide tape is removed after the sealing film is formed.

JP 2002-151254 A JP 2003-249354 A

  When sealing by covering a light emitting element such as an organic EL element with a film, a crack may progress from the edge of the film toward the inside of the film. For this reason. It is necessary to prevent cracks from occurring at the edges of the film.

  An example of a problem to be solved by the present invention is to prevent cracks from occurring at the edge of the coating film when the light emitting element is covered with the coating film.

The invention according to claim 1 is a substrate;
A light emitting device formed on the substrate;
A coating film formed on the substrate and covering the light emitting element;
With
The substrate has an uncovered region not covered by the coating film;
In the boundary between the non-covering region and the coating film, the corner of the edge of the coating film is a light-emitting device that is curved when the inner angle of the intersection of two adjacent straight lines is 90 degrees or less. .

It is sectional drawing which shows the structure of the light-emitting device which concerns on embodiment. It is a top view of a light-emitting device. It is the figure which showed the coating film in FIG. 2 with the continuous line. It is sectional drawing for demonstrating the method of forming a coating film in a board | substrate. FIG. 6 is a plan view for explaining the method for manufacturing the light emitting device according to the first embodiment. 6 is a plan view illustrating a configuration of a light emitting device according to Example 2. FIG. 6 is a plan view showing a configuration of a light emitting device according to Example 3. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  FIG. 1 is a cross-sectional view illustrating a configuration of a light emitting device 10 according to the embodiment. FIG. 2 is a plan view of the light emitting device 10 shown in FIG. In FIG. 2, the coating film 140 is omitted. 1 is a cross-sectional view taken along line AA of FIG. FIG. 3 is a diagram showing the coating film 140 in FIG. 2 by a solid line.

  The light emitting device 10 according to the embodiment is, for example, a lighting device or a display, and includes a substrate 100, a light emitting element 102, and a coating film 140. The light emitting element 102 is formed on the substrate 100. The covering film 140 is formed on the substrate 100 and covers the light emitting element 102. The substrate 100 includes a region not covered by the coating film 140 (non-covering region: for example, a portion located in an opening 142 described later and a portion located in the scribe line 12 of the substrate 100). At the boundary between the non-covering region and the coating film 140, the corner of the edge of the coating film 140 becomes a curve when the inner angle of the extending intersection of two adjacent straight lines at the edge of the coating film 140 is 90 degrees or less. ing. The light emitting element 102 is, for example, an organic EL element. Details will be described below.

  The substrate 100 is a transparent substrate such as a glass substrate or a resin substrate. The substrate 100 may have flexibility. In this case, the thickness of the substrate 100 is, for example, not less than 10 μm and not more than 1000 μm. Also in this case, the substrate 100 may be formed of either an inorganic material or an organic material. The substrate 100 is, for example, a polygon such as a rectangle. Note that in the case where the substrate 100 is a resin substrate, an inorganic material film such as a silicon oxide film is formed on a surface of the substrate 100 where the light emitting element 102 is formed. Accordingly, moisture or the like can be prevented from passing through the substrate 100 and reaching the light emitting element 102.

  An insulating layer 160 is formed on the substrate 100. The insulating layer 160 has an opening 162. A light emitting element 102 is formed in the opening 162. In other words, a region where the light emitting element 102 is to be formed is defined. The insulating layer 160 is formed of a material such as polyimide, silicon oxide, or silicon nitride.

  The light emitting element 102 has a configuration in which the organic layer 120 is sandwiched between the first electrode 110 and the second electrode 130. At least one of the first electrode 110 and the second electrode 130 is a translucent electrode. The remaining electrodes are made of, for example, a metal selected from the first group consisting of Al, Mg, Au, Ag, Pt, Sn, Zn, and In, or an alloy of a metal selected from the first group. Formed by a metal layer. The material of the translucent electrode is, for example, an inorganic material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), a conductive polymer such as a polythiophene derivative, or a network using nanowires made of silver or carbon. Electrode. For example, in the case of the bottom emission type light emitting element 102, the first electrode 110, the organic layer 120, and the second electrode 130 are stacked on the substrate 100 in this order. It is a translucent electrode, and the second electrode 130 is an electrode that reflects light such as Al. Further, in the case of the top emission type light emitting element 102 having a configuration in which the first electrode 110, the organic layer 120, and the second electrode 130 are stacked in this order on the substrate 100, the first electrode 110 is It is an electrode that reflects light, such as Al, and the second electrode 130 is a translucent electrode. Alternatively, both electrodes (the first electrode 110 and the second electrode 130) may be translucent electrodes to form a translucent light emitting device (dual emission type).

  The organic layer 120 has a configuration in which, for example, a hole transport layer, a light emitting layer, and an electron transport layer are stacked in this order. A hole injection layer may be formed between the hole transport layer and the first electrode 110. In addition, an electron injection layer may be formed between the electron transport layer and the second electrode 130. The layer of the organic layer 120 may be formed by a coating method or a vapor deposition method, and a part thereof may be formed by a coating method and the rest may be formed by a vapor deposition method. The organic layer 120 may be formed by a vapor deposition method using a vapor deposition material, and the organic layer 120 may be formed by an ink jet method, a printing method, or a spray method using a coating material.

  Terminals 112 and 132 are formed on the surface of the substrate 100 where the light emitting element 102 is formed. The terminal 112 is electrically connected to the first electrode 110, and the terminal 132 is electrically connected to the second electrode 130. Specifically, the organic layer 120 is not formed on a part of the first electrode 110 and serves as the terminal 112. The terminal 132 has the same layer as the first electrode 110. In the example shown in this figure, the terminal 112 is connected to the first electrode 110 via the wiring 116, and the terminal 132 is connected to the second electrode 130 via the wiring 136. Each of the wirings 116 and 136 has the same layer as the first electrode 110. The terminals 112 and 132 are connected to the circuit board through conductive members such as anisotropic conductive films, lead terminals, and bonding wires. A control circuit is formed on the circuit board.

  In the example shown in this figure, the terminal 112 has a configuration in which a second layer 114 is laminated on the layer of the first electrode 110. The terminal 132 has a configuration in which a second layer 134 is stacked on the same layer as the first electrode 110. The second layers 114 and 134 are made of a material having a lower resistance than the material forming the first electrode 110, for example, a metal. The second layers 114 and 134 have a configuration in which, for example, Mo, Al, and Mo are stacked in this order. In addition, other metals may be added to Mo and Al. Note that the second layers 114 and 134 may also be formed on at least a part of the wirings 116 and 136.

The covering film 140 is formed using a film forming method such as an ALD method or a CVD method. In the case of being formed by the ALD method, the coating film 140 is formed of a metal oxide film such as aluminum oxide, and the film thickness thereof is, for example, 10 nm to 200 nm, preferably 50 nm to 100 nm. When formed by the CVD method, the coating film 140 is formed of an inorganic insulating film such as a silicon oxide film, and the film thickness thereof is, for example, not less than 0.1 μm and not more than 10 μm. By providing the coating film 140, the light emitting element 102 is protected from moisture and the like. The covering film 140 may be formed by a sputtering method. In this case, the covering film 140 is formed of an insulating film such as SiO ₂ or SiN. In that case, the film thickness is 10 nm or more and 1000 nm or less. Note that when the coating film 140 is formed of an inorganic film and the surface of the substrate 100 on which the coating film 140 is formed is formed of an inorganic material, sealing is performed by bonding the coating film 140 and the substrate 100. The stopping performance is improved.

  The coating film 140 is not formed on the edge of the substrate 100. In other words, the outer edge of the coating film 140 is located inside the substrate 100 with respect to the edge of the substrate 100. A region located between the edge of the substrate 100 and the outer edge of the coating film 140 in the substrate 100 is a second non-covering region. This second uncovered region extends along each side of the substrate 100. The boundary between the second non-covering region and the coating film 140 also extends along each side of the substrate 100, and the portion corresponding to the corner of the substrate 100 is formed by two adjacent straight lines ( For example, a curved line (for example, a circular arc) is formed when an internal angle of an extending intersection point of a portion corresponding to each of two sides of the substrate 100 that intersect each other is 90 degrees or less.

  The terminals 112 and 132 described above are formed near the edge of the substrate 100. The coating film 140 has an opening 142 at a position overlapping the terminals 112 and 132. A region of the substrate 100 that overlaps with the opening 142 is a first uncovered region. The opening 142 has a corner portion, and the corner portion is curved when the inner angle at the intersection of two adjacent straight lines extending is 90 degrees or less. In the example shown in the figure, the corner is a curve (for example, an arc).

  The two uncovered regions described above are formed by removing the coating film 140. As a method of partially removing the coating film 140, for example, a lift-off method can be used. In this case, when the lift-off layer 200 is partially applied, if the planar shape of the lift-off layer 200 is the above-described shape of the non-covered region, the planar shape of the non-covered region can be the above-described shape. The lift-off layer 200 may be formed by, for example, a screen printing method, or may be applied so as to draw a desired shape by moving an application unit.

  Note that when the coating film 140 is formed, the non-covered region may be formed by covering the region that should be the non-covered region with a metal mask.

  Next, a method for manufacturing the light emitting device 10 will be described. First, the first electrode 110 and the terminals 112 and 132 are formed on the substrate 100. The first electrode 110 and the terminals 112 and 132 are formed using, for example, a vapor deposition method or a sputtering method. Next, the insulating layer 160 is formed between the first electrode 110 and the terminal 132. Next, the organic layer 120 is formed on the first electrode 110.

  Next, the second electrode 130 is formed, and the coating film 140 is further formed. The second electrode 130 is formed using, for example, a sputtering method or a vapor deposition method, and the coating film 140 is formed using, for example, an ALD method or a CVD method.

  FIG. 4 is a cross-sectional view for explaining a method of forming the coating film 140 on the substrate 100. As described above, the coating film 140 does not cover the terminals 112 and 132. Further, the vicinity of the edge of the substrate 100 is not covered with the coating film 140. In order to do this, for example, before forming the coating film 140, the region where the terminals 112 and 132 are formed and the region near the edge of the substrate 100 are covered with the lift-off layer 200. The lift-off layer 200 is made of, for example, an organic material. The glass transition temperature or phase transition temperature (for example, melting point) of the lift-off layer 200 is lower than the glass transition temperature or phase transition temperature (for example, melting point) of the coating film 140. The linear expansion coefficient of the material forming the lift-off layer 200 is preferably larger than the linear expansion coefficient of the material forming the coating film 140.

  Then, after forming the coating film 140, the substrate 100 is heated and cooled. At this time, a crack is generated in a portion of the coating film 140 located above the lift-off layer 200. When the vicinity of the terminal 112 and the terminal 132 is washed with a solution that dissolves the lift-off layer 200, the solution comes into contact with the lift-off layer 200 through a crack generated in the coating film 140, and the lift-off layer 200 is removed. . At this time, the portion of the coating layer 140 that was located above the lift-off layer 200 is removed.

  Cracks may occur at the corners of the end of the coating film 140. This crack is generated, for example, when stress is applied to the substrate 100 when a conductive member is connected to the terminals 112 and 132. Further, the crack may occur when the coating film 140 is lifted off. When a crack occurs at the end of the coating film 140, the crack progresses toward the light emitting element 102. On the other hand, in the present embodiment, the corner portion of the end portion of the coating film 140 is a curve when the inner angle at the intersection of two adjacent straight lines extending is 90 degrees or less. Therefore, it is possible to suppress the stress from concentrating on the corner and cracking the coating film 140. In particular, when the internal angle of the intersection of two adjacent straight lines extends is 90 degrees or less, an acute angle is formed and a crack is likely to occur, so the effect of the present embodiment is increased.

Example 1
The light emitting device 10 according to the present example has the same configuration as the light emitting device 10 according to the embodiment, except for the manufacturing method.

  FIG. 5 is a plan view for explaining the method for manufacturing the light emitting device 10 according to the present embodiment. In this embodiment, the plurality of light emitting devices 10 are simultaneously formed with the substrates 100 being connected to each other. Then, after the coating film 140 is formed, the plurality of light emitting devices 10 are separated from each other using a dicing blade or the like. Here, when the coating film 140 is formed on the scribe line 12, a large crack may occur in the coating film 140 when the light emitting devices 10 are separated from each other. For this reason, the coating film 140 is formed away from the scribe line 12 over the entire circumference. Specifically, before the coating film 140 is formed, the lift-off layer 200 is applied to the scribe line 12 and the vicinity thereof.

  For this reason, when the plurality of light emitting devices 10 are separated from each other, it is possible to prevent the coating film 140 from being cracked.

(Example 2)
FIG. 6 is a plan view illustrating the configuration of the light emitting device 10 according to the second embodiment. The light emitting device 10 according to this example has the same configuration as the light emitting device 10 according to the embodiment except for the following points. In FIG. 6, illustration of the second electrode 130 and the terminal 132 is omitted for the sake of explanation.

  In this embodiment, the light emitting device 10 includes a plurality of light emitting elements 102. An insulating layer 160 is formed between the adjacent light emitting elements 102. A terminal 112 is formed for each of the plurality of light emitting elements 102. The plurality of terminals 112 are arranged on the edge of the substrate 100 side by side. All the terminals 112 are located inside the opening 142 of the coating film 140.

  Note that the terminal 132 is also disposed inside the opening 142 in the same manner as the terminal 112. The opening 142 including the terminal 132 inside and the opening 142 including the terminal 112 inside may be the same opening 142 or may be different from each other.

  Also according to the present embodiment, the occurrence of cracks at the corners of the edge of the coating film 140 can be suppressed.

(Example 3)
FIG. 7 is a plan view illustrating a configuration of the light emitting device 10 according to the third embodiment, and corresponds to FIG. 6 in the second embodiment. The light emitting device 10 according to the present example has the same configuration as that of the light emitting device 10 according to Example 2 except for the following points.

  In this embodiment, the light emitting device 10 is a display and has a plurality of light emitting elements 102 arranged in a matrix.

  Specifically, the plurality of first electrodes 110 extend in parallel to each other, and the plurality of second electrodes 130 extend in a direction parallel to each other and intersecting the first electrode 110 (for example, a direction orthogonal to each other). ing. A light emitting element 102 is formed at each intersection of the first electrode 110 and the second electrode 130. Specifically, the insulating layer 160 is formed over the plurality of first electrodes 110. An opening is formed in a portion of the insulating layer 160 located at the intersection of the first electrode 110 and the second electrode 130. An organic layer 120 is provided in the opening.

  The terminal 112 is electrically connected to each of the plurality of first electrodes 110, and the terminal 132 is electrically connected to each of the plurality of second electrodes 130. The plurality of terminals 112 and 132 are all disposed along the edge of the substrate 100. In the example shown in this drawing, the plurality of terminals 112 and 132 are all disposed along the same side of the substrate 100 and are disposed inside the same opening 142. However, the terminal 112 and the terminal 132 may be disposed along different sides of the substrate 100. In this case, the terminal 112 and the terminal 132 are disposed inside different openings 142.

  Further, a partition wall may be formed over the insulating layer 160. In this case, the partition is located between the plurality of second electrodes 130. The cross section of the partition wall has a trapezoid whose upper base is longer than the lower base. A conductive layer made of the same material as that of the second electrode 130 is formed on the upper surface of the partition wall. The partition is provided to separate the adjacent second electrodes 130 from each other when the second electrodes 130 are formed by vapor deposition or sputtering. Therefore, the partition wall is formed after the insulating layer 160 is formed and before the second electrode 130 is formed (preferably before the organic layer 120 is formed).

  Also according to the present embodiment, the occurrence of cracks at the corners of the edge of the coating film 140 can be suppressed.

  As mentioned above, although embodiment and the Example were described with reference to drawings, these are illustrations of this invention and can also employ | adopt various structures other than the above.

10 Light-emitting device 12 Scribe line (second uncovered region)
100 Substrate 102 Light-emitting element 112 Terminal 132 Terminal 140 Covering film 142 Opening (non-covering region)

Claims (5)

A substrate,
A light emitting device formed on the substrate;
A coating film formed on the substrate and covering the light emitting element;
With
The substrate has an uncovered region not covered by the coating film;
The light-emitting device in which the corner of the edge of the coating film is a curve at the boundary between the non-covering region and the coating film when the inner angle of the intersection of two adjacent straight lines is 90 degrees or less. The light-emitting device according to claim 1.
The uncovered region is an opening formed in the coating film,
Furthermore, a light-emitting device provided with a terminal located in the opening and electrically connected to the light-emitting element. The light-emitting device according to claim 2.
A light emitting device comprising the second uncovered region formed along an edge of the substrate. The light emitting device according to claim 3.
The substrate is polygonal;
A boundary between the second non-covering region and the coating film extends along each side of the substrate, and a portion corresponding to a corner of the substrate is a curved light-emitting device. The light-emitting device according to claim 4.
The light emitting device in which the non-covering region and the second non-covering region are formed by removing the coating film.

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