JP2010135164A - Electroluminescence display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the light-emitting efficiency of an electroluminescence display device. <P>SOLUTION: A reflective layer 121 in the electroluminescence display device 100 has an inter-pixel reflective layer 126 arranged at a location corresponding to a zone X where a lower electrode 122 and an electroluminescence layer 123 are brought into contact with each other, and an out-pixel reflective layer 127 arranged outside the location corresponding to the zone X. In the electroluminescence display device 500, the thickness of an electroluminescence layer 523(R) at the other pixel 520(R) adjacent to one pixel 520(B) becomes a thickness at which both a reflection factor at the other pixel 520(R) of light emitted by one pixel 520(B) and the luminance of the light emitted by the other pixel 520(R) simultaneously exhibit peaks. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electroluminescent display device.

  In recent years, electroluminescent display devices have attracted attention and are being put into practical use as thin and light self-luminous display devices. An electroluminescent display device emits light by injecting positive and negative charges into an electroluminescent layer formed on a substrate such as glass, and converting electric energy into light energy. At this time, in order to efficiently extract isotropically generated light to the front surface of the substrate, a reflective layer that reflects light is provided below the electroluminescent layer. This reflective layer is external to the electroluminescent display device. Since the light is also reflected, it is difficult to see the screen due to so-called reflection, or the black display becomes bright and the contrast ratio is lowered. In order to solve this problem, it is conceivable to attach an antireflection film made of a circularly polarizing plate to the front surface of the electroluminescent display device, but this circularly polarizing plate emits light from an electroluminescent layer having no specific polarization. Since about half is absorbed, there is a problem that the luminous efficiency of the electroluminescent display device is lowered.

In order to solve this problem, in Patent Document 1, in addition to a circularly polarizing plate, an electroluminescence having an additional cholesteric liquid crystal layer that transmits circularly polarized light in one direction and reflects circularly polarized light in the opposite direction is added. A display device is disclosed. In the invention described in this document, the circularly polarized light absorbed by the circularly polarizing plate is reflected by the cholesteric liquid crystal layer, and further reflected by the reflecting layer, so that the polarization direction is reversed, and as a result, it can be transmitted through the circularly polarizing plate. become. In this way, since the circularly polarized light absorbed by the circularly polarizing plate can be taken out to the front surface of the electroluminescence display device, the light emission efficiency is improved.
JP 2002-215067 A

  As described above, in the electroluminescence display device, light emission from the electroluminescence layer is isotropic. For this reason, some of the light incident obliquely on the electroluminescent substrate cannot be reused even if it is reflected by the cholesteric liquid crystal layer described above. This will be described with reference to FIG.

  FIG. 8 is a schematic cross-sectional view showing the structure of a conventional electroluminescent display device 800. In the electroluminescent display device 800, a large number of TFTs (thin layer transistors) 810 are formed on a substrate 801 made of glass or the like, and each TFT 810 turns on or off a pixel 820 that is also formed on the substrate 801. Control. In the figure, reference numeral 802 is a gate insulating layer, reference numeral 803 is an interlayer insulating layer, reference numeral 804 is an insulating protective layer, reference numeral 811 is a channel made of polysilicon, reference numeral 812 is a gate electrode, reference numeral 813 is a source electrode, reference numeral 814 Is a drain electrode. On the protective layer 804, a reflective electrode 821 made of a metal layer, a lower electrode 822, an electroluminescence layer 823, and an upper electrode 824 made of a conductive transparent thin film such as ITO (indium tin oxide) are formed. ing. Here, the reflective electrode 821 is electrically connected to the drain electrode 814, and can supply a positive charge to the lower electrode 822 and reflect light rays on the surface thereof. The electroluminescent layer 823 emits light having a wavelength corresponding to the material of the electroluminescent layer 823 by combining holes supplied from the lower electrode 822 and electrons supplied from the upper electrode 824. A pixel 820 (B) shown on the left side in the figure is a pixel that emits blue light, and a pixel 820 (R) shown on the right side in the figure is a pixel that emits red light. Each pixel 820 is separated by an insulating pixel separation layer 805.

  Further, a transparent sealing substrate 830 made of glass or the like is provided above the substrate 801, and an inert gas such as nitrogen gas and a desiccant (not shown) are enclosed in a space 840 with the substrate 801. ing. The sealing substrate 830 is provided with a circularly polarized light reflecting plate 831 made of cholesteric liquid crystal, a quarter wavelength plate 832, and a linearly polarizing plate 833. The circularly polarized light reflecting plate 831 has a property of transmitting circularly polarized light in one direction and reflecting circularly polarized light in the opposite direction. Further, the quarter-wave plate 832 and the linearly polarizing plate 833 constitute a circularly polarizing plate 834, which converts only a specific linearly polarized component of light incident from the top in the figure into circularly polarized light in a specific direction. While transmitting, only circularly polarized light in a specific direction of light incident from the lower part of the figure is converted into specific linearly polarized light and transmitted, and the rest is absorbed. The circularly polarizing plate 834 and the circularly polarizing reflection plate 831 constitute a polarizing member 835.

  Note that, as shown in the figure, a form in which light is extracted in the direction in which the pixel 820 of the substrate 801 is formed is generally called a top emission method. Further, a material in which the material of the electroluminescence layer 823 is an organic material is often called an organic electroluminescence display device.

  Here, some of the light from the electroluminescent layer 823 of the pixel 820 (B) is emitted obliquely with respect to the substrate 801 as indicated by A in the drawing. These lights do not have a specific polarization component. Therefore, when the light A reaches the polarizing member 835, only the light of the circularly polarized component in the direction in which the light can be transmitted through the circularly polarizing reflection plate 831 is transmitted through the polarizing member 835, and becomes the linearly polarized light indicated by B in the drawing. It is taken out to the front surface of the display device 800. On the other hand, the light of the circularly polarized light component that cannot be transmitted through the circularly polarized light reflecting plate 831 is reflected as indicated by C and D in the figure.

  At this time, the light C is reflected by the circularly polarized light reflection plate 831 and then enters the pixel separation layer 805. At this time, since the reflective electrode 821 does not exist under the pixel separation layer 805, the light C is absorbed without being reflected again, and can hardly be taken out to the front surface of the electroluminescence display device 800.

  The light D is incident on the pixel 820 (R) adjacent to the pixel 820 (B). At this time, although the reflective electrode 821 is formed under the pixel 820 (R) similarly to the pixel 820 (B), the light D cannot be reflected and extracted sufficiently. Because the layer thickness of the electroluminescent layer 823 is determined in accordance with the main wavelength of the emitted light, the layer thickness of the electroluminescent layer 823 in the pixel 820 (B) and the pixel 820 (R) is different. The blue light emitted from the pixel 820 (B) is attenuated by optical interference in the electroluminescent layer 823 in the pixel 820 (R).

  Note that the “main wavelength” refers to the wavelength having the strongest intensity among the light emitted from the electroluminescent layer 823 in the pixel 820.

  FIG. 9 is a graph showing the reflectance of light in the electroluminescent layer 823 in the red pixel 820 (R). Here, the horizontal axis represents the wavelength λ [nm] of light incident on the electroluminescent layer 823, the vertical axis represents the reflectance R [%], and the thickness of the electroluminescent layer 823 was 750 [nm].

  As indicated by hatching in the figure, the reflectance R is very low in the region where the wavelength of the light that is blue light is around 450 [nm]. That is, the light D from the pixel 820 (B) incident on the pixel 820 (R) can hardly be collected.

  As can be understood from the above description, among the light emitted from a specific pixel 820 and reflected by the circularly polarized light reflector 831, the light reaching the pixel separation layer 805 and the light reaching the adjacent pixel 820 are electroluminescent. If the light can be efficiently taken out to the front surface of the sense display device 800, the light emission efficiency can be expected to be further improved.

  This invention is made | formed in view of this viewpoint, Comprising: The objective is to improve the luminous efficiency of an electroluminescent display apparatus.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  (1) A substrate, a plurality of pixels formed on one surface of the substrate, having a reflective layer, a lower surface electrode, an electroluminescence layer, and an upper surface electrode, and disposed opposite the pixels. A polarizing member having a circularly polarizing reflector that transmits circularly polarized light in one direction and reflects circularly polarized light in the opposite direction, and a circularly polarizing plate that converts linearly polarized light and circularly polarized light into each other; And the reflective layer is disposed in a position corresponding to a region where the lower surface electrode and the electroluminescent layer are in contact with each other, the lower surface electrode, and the electroluminescence An electroluminescent display device comprising: an out-pixel reflection layer disposed outside a position corresponding to a region in contact with the layer.

  (2) The electroluminescent display device according to (1), wherein the reflective layer is formed by integrally forming the intra-pixel reflective layer and the extra-pixel reflective layer.

  (3) In the electroluminescence display device according to (2), the extra-pixel reflective layer is not electrically connected to a member other than the bottom electrode.

  (4) The electroluminescent display device according to (1), wherein the reflective layer is formed by separately forming the intra-pixel reflective layer and the extra-pixel reflective layer.

  (5) The electroluminescent display device according to (4), wherein the extra-pixel reflective layer is formed on the same surface as the surface on which the intra-pixel reflective layer is formed.

  (6) The electroluminescent display device according to (4), wherein the extra-pixel reflective layer is exposed on an upper surface of the pixel.

  (7) In the electroluminescence display device according to (6), the extra-pixel reflection layer is formed on an upper surface of the upper electrode.

  (8) The electroluminescent display device according to (1), wherein the reflective layer includes at least one component selected from silver, aluminum, rhodium, iron, nickel, and chromium.

  (9) The electroluminescence display device according to (1), wherein a pixel separation layer having an extinction coefficient of 0.15 or less with respect to visible light is provided between the plurality of pixels.

  (10) A substrate, a plurality of pixels formed on one surface of the substrate and having a reflective layer, a lower surface electrode, an electroluminescence layer, and an upper surface electrode, and disposed opposite to the pixels. A polarizing member having a circularly polarizing reflector that transmits circularly polarized light in one direction and reflects circularly polarized light in the opposite direction, and a circularly polarizing plate that converts linearly polarized light and circularly polarized light into each other; The one pixel in which the thickness of the electroluminescent layer in another pixel adjacent to the one pixel changes in accordance with the change in the thickness of the electroluminescent layer in the other pixel is The thickness at which the reflectance of the emitted light at the other pixel and the luminance of the light emitted by the other pixel that changes in accordance with the change in the thickness of the electroluminescent layer at the other pixel both show a peak. The electroluminescence table Apparatus.

を満たすｎ，ｍについて、

を満たすエレクトロルミネセンス表示装置。 (11) (10), the thickness t ₂ of the electroluminescent layer in the other pixel, the _one of the main wavelength of light one pixel emits _lambda, a main wavelength of light which the other pixels are emitted When each of λ ₂ , n, and m is a positive natural number,

N and m satisfying

An electroluminescent display device that satisfies the above requirements.

であるか、

のいずれかであることを特徴とするエレクトロルミネセンス表示装置。 (12) In (11), the one pixel is a pixel that emits blue light, the other pixel is a pixel that emits red light, and the n and m are respectively

Or

An electroluminescent display device characterized by being any one of the above.

  According to the invention disclosed in the present application, the light emission efficiency of the electroluminescent display device can be improved.

  A preferred first embodiment of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing the structure of the electroluminescent display device 100 according to the first embodiment. Similarly to the conventional electroluminescent display device 800 (see FIG. 8), the electroluminescent display device 100 according to the present embodiment is also formed on the substrate 101 by a large number of TFTs 110 formed on the substrate 101 made of glass or the like. The lighting or extinguishing of the pixel 120 is controlled.

  In the figure, reference numeral 102 denotes a gate insulating layer, reference numeral 103 denotes an interlayer insulating layer, reference numeral 104 denotes a protective layer, reference numeral 105 denotes a pixel separation layer, and reference numeral 106 denotes an insulating flattening layer. Reference numeral 111 denotes a channel made of polysilicon or the like, reference numeral 112 denotes a gate electrode, and reference numerals 113 and 114 denote a source electrode and a drain electrode, respectively. In addition, although the drain electrode 114 is shown in two places in the figure, both are electrically connected. Reference numeral 121 denotes a reflective layer, and reference numeral 122 denotes a lower electrode connected to the source electrode, which supplies electrons to the electroluminescent layer 123. Reference numeral 124 denotes an upper electrode made of a conductive transparent thin layer such as ITO, which supplies holes to the electroluminescent layer 123. The upper electrode 124 and the drain electrode 114 are electrically connected via the intermediate electrode 125. In the present embodiment, the reflective layer 121 does not serve as an electrode as shown in the figure, but the source electrode 113 and the lower electrode 122 are connected via the reflective layer 121 as in the conventional electroluminescent display device 800. Anyway. The reflective layer 121 preferably has a high visible light reflectivity, and is preferably a layer made of silver, aluminum, rhodium, iron, nickel, or chromium, an alloy made of two or more of these components, or at least A metal layer containing these components can be used.

  The sealing substrate 130 is a transparent substrate such as glass or plastic, on which a circularly polarized light reflection plate 131, a quarter wavelength plate 132, and a linear polarization plate 133 are provided. The quarter wavelength plate 132 and the linearly polarizing plate 133 constitute a circularly polarizing plate 134, and the circularly polarizing plate 134 and the circularly polarizing reflecting plate 131 constitute a polarizing member 135. In the space 140 between the sealing substrate 130 and the substrate 101, an inert gas such as nitrogen gas and a desiccant (not shown) are sealed, thereby preventing the electroluminescent layer 123 from being deteriorated by moisture or oxygen.

  Here, the electroluminescent layer 123 emits light by injecting electrons in a region (X in the drawing) in contact with the lower electrode 122. In the present embodiment, the reflection layer 121 includes an out-pixel reflection layer 127 that integrally extends outside the position corresponding to the region X in addition to the in-pixel reflection layer 126 formed at the position corresponding to the region X. .

  In this embodiment, a part of the light A emitted obliquely from the electroluminescent layer 123 with respect to the substrate is extracted as light B on the front surface of the electroluminescent display device 100, and the rest is reflected as light C. As described above, the light enters the pixel separation layer 105. At this time, since the extra-pixel reflection layer 127 is formed below the pixel separation layer 105, the light C is reflected by the extra-pixel reflection layer 127, the circular polarization direction is reversed, and the polarization member 135 is transmitted. It is taken out to the front surface of the electroluminescent display device 100. For this reason, the luminous efficiency of the electroluminescent display device 100 is improved. At this time, in order to prevent a short circuit, the extra-pixel reflective layer 127 must be prevented from being electrically connected to members other than the lower electrode 122, particularly the intermediate electrode 125. In order to suppress absorption of light C by the pixel separation layer 105, the material of the pixel separation layer 105 preferably has an extinction coefficient of 0.15 or less, more preferably 0.10 or less, more preferably visible light. Preferably it is 0.08 or less.

  In this embodiment, since the in-pixel reflection layer 126 and the out-pixel reflection layer 127 can be formed at the same time, it can be realized only by changing the mask shape when forming the reflection layer 121, and the manufacturing cost is low. In this embodiment, a part of the extra-pixel reflective layer 127 is not covered with the lower electrode 122 and is exposed to the pixel isolation layer 105. However, this generally means that the lower electrode 122 has low transparency. Because. However, the front surface of the extra-pixel reflective layer 127 may be covered with the lower electrode 122.

  Note that insulating layers such as the gate insulating layer 102, the interlayer insulating layer 103, the protective layer 104, the pixel isolation layer 105, and the planarization layer 106 may be omitted or added as appropriate for manufacturing reasons or structural differences. May be. Further, the electroluminescent layer 123 may not be formed on the pixel separation layer 105 but may be formed only in the region X. Furthermore, in this embodiment, the upper electrode 124 is connected to the drain electrode 114 and the lower electrode 122 is connected to the source electrode 113, but this can be reversed. Further, the extra-pixel reflection layer 127 may be provided for all the pixels 120 of the electroluminescent display device 100 or may be provided only for specific pixels 120. For example, it can be provided only for the pixel 120 that emits a specific color with low luminance such as blue.

  Next, a preferred second embodiment of the present invention will be described.

  FIG. 2 is a schematic cross-sectional view showing the structure of the electroluminescent display device 200 according to the second embodiment. Since the electroluminescent display device 200 is the same as the electroluminescent display device 100 according to the first embodiment except that the structure of the reflective layer 221 is different, detailed description of common parts is omitted. .

  In the present embodiment, as shown in the figure, the in-pixel reflection layer 226 and the out-pixel reflection layer 227 are formed separately, and they are not electrically connected. Even in this case, the light C incident on the pixel separation layer 205 can be extracted to the front surface of the electroluminescent display device 200.

  In this embodiment, even if the extra-pixel reflective layer 227 is short-circuited with a member other than the lower electrode 222, for example, the intermediate electrode 225, the operation is not affected, and the electroluminescence display device 200 has high reliability. Further, since the in-pixel reflection layer 226 and the out-pixel reflection layer 227 can be formed at the same time, it can be realized only by changing the mask shape when forming the reflection layer 221, and the manufacturing cost is low.

  Subsequently, a preferred third embodiment of the present invention will be described.

  FIG. 3 is a schematic cross-sectional view showing the structure of an electroluminescent display device 300 according to the third embodiment. The electroluminescent display device 300 is also the same as the electroluminescent display device 100 according to the first embodiment except that the structure of the reflective layer 321 is different. Therefore, detailed description of common parts is omitted. .

  In the present embodiment, as shown in the drawing, an extra-pixel reflection layer 327 is formed on the upper surface of the pixel separation layer 305. Even in this case, the light C incident on the pixel separation layer 305 can be extracted to the front surface of the electroluminescent display device 300.

  In the present embodiment, since the light C does not pass through the pixel separation layer 305, the light C is less attenuated than in the first and second embodiments, and the luminous efficiency of the electroluminescent display device 300 can be further increased. it can.

  Subsequently, a preferred fourth embodiment of the present invention will be described.

  FIG. 4 is a schematic cross-sectional view showing the structure of an electroluminescent display device 400 according to the fourth embodiment. The electroluminescent display device 400 is also the same as the electroluminescent display device 100 according to the first embodiment except that the structure of the reflective layer 421 is different. Therefore, detailed description of common parts is omitted. .

  In the present embodiment, as shown in the figure, the extra-pixel reflection layer 427 is formed so as to be exposed on the upper surface of the upper electrode 424. In this case, the light C is reflected by the extra-pixel reflection layer 427 without passing through the layer formed on the substrate 401, so that there is almost no attenuation, and the electroluminescent display device 400 has a lower intensity than in the third embodiment. Luminous efficiency can be further increased. Further, since the electrical resistance of the extra-pixel reflective layer 427 itself is small, the electrical resistance of the upper electrode 424 having a relatively large specific resistance can be lowered.

  Next, a preferred fifth embodiment of the present invention will be described.

  FIG. 5 is a schematic cross-sectional view partially showing the structure of the electroluminescent display device 500 according to the fifth embodiment. For the sake of simplicity, the figure shows a pixel 520 (B) that emits blue light on the left side, a pixel 520 (R) that is adjacent to the pixel 520 (B) and emits red light on the right side, and shows only the main part. ing. In the drawing, a planarization layer 506, a reflection layer 521, a lower electrode 522, a pixel separation layer 505, and an upper electrode 524 are shown. In addition, a sealing substrate 530 and a polarizing member 535 are arranged above the pixel 520 with a space 540 filled with nitrogen gas and a desiccant (not shown) interposed therebetween.

Here, the layer thickness of the electroluminescence layer 523 (B) of the pixel 520 (B) is t ₁ , the layer thickness of the electroluminescence layer 523 (R) of the pixel 520 (R) is t ₂ , and the pixel 520 (B ) ₁ a main wavelength of the blue light λ _emanating, and ₂ a main wavelength λ of the pixel 520 (R) emitted red light. Further, in the drawing, a part of the light A emitted obliquely from the pixel 520 (B) is extracted as light B to the front surface of the electroluminescence display device 500, and the remaining light D is adjacent to the pixel 520 (B). A state in which light is incident on the pixel (R) is shown.

As described above, the light D is interfering with the electroluminescent layer 523 (R), the thickness t ₂ in order to reflect light well D efficiency, as appropriate with respect to the blue light emitted by the pixel 520 (B) Must be set. However, the electroluminescent layer 523 (R) also interferes with the red light emitted from the pixel 520 (R), and the luminance of the pixel 520 (R) itself changes depending on the layer thickness. In determining the layer thickness of 523 (R), both must be taken into account.

6 shows the thickness t ₂ of the electroluminescent layer 523 (R), reflectivity R, the relationship between the brightness L and the chromaticity change amounts [Delta] x. Incidentally, the layer thickness t ₂ shown in the figure is a value in terms of optical thickness.

となる近辺に現れる。ここで、ｎは１以上の自然数である。 (A) shows the reflectance R [%] of the blue light in the pixel 520 (R) with respect to the layer thickness t ₂ when the wavelength λ ₁ of the blue light from the pixel 520 (B) is 450 [nm]. It is the graph shown. As can be seen from the graph, the reflectivity R periodically changes with the change of the layer thickness t ₂ due to the optical effect, and its maximum value is approximately,

Appears in the vicinity. Here, n is a natural number of 1 or more.

となる近辺に現れる。ここで、ｍは１以上の自然数である。 Further, (b) is a graph showing the luminance L of the pixel 520 (R) with respect to the layer thickness t ₂ when the wavelength λ ₂ of the red light from the pixel 520 (R) is 600 [nm]. is there. As can be seen from the graph, the luminance also periodically changes with the change of the layer thickness t ₂ due to the optical effect, and the maximum value is almost the same.

Appears in the vicinity. Here, m is a natural number of 1 or more.

That is, be determined layer thickness t ₂ so as to satisfy the equation (1) and formula (2) at the same time, can be both high and height of the luminance L of the reflectivity R. In other words, the reflectance of the pixel 520 (R), which is another adjacent pixel, of the light emitted from the pixel 520 (B), which is one pixel, and the luminance of the light, which is emitted from the pixel 520 (R), which is another pixel. DOO are both by determining the thickness t ₂ of the electroluminescent layer 523 (R) of the pixel 520 which is the other pixels to indicate the peak (R), light emission of the pixels 520 (R) is another pixel The light D emitted from the pixel 520 (B), which is one pixel, can be efficiently reflected and taken out to the front surface of the electroluminescence display device 500 while ensuring the luminance.

を満たすｎ，ｍについて、

を満たすように定めればよいことになる。なお、ここでは許容誤差を±２０［ｎｍ］としたが、より好ましくは±１５［ｎｍ］とすればよく、さらに好ましくは±１０［ｎｍ］とする。その場合、式（３）及び式（４）の右辺の値を変更すればよい。 By the way, the wavelength λ _{1, the} wavelength λ ₂ , and the layer thickness t ₂ slightly vary due to variations in material properties and manufacturing errors. This, considering the practical performance, no problem by allowing an error of about ± 20 [nm] is in determining the thickness t _2. When formula (1) and formula (2) are rewritten in consideration of the tolerance, the layer thickness t ₂ is

N and m satisfying

It will be sufficient if it is determined to satisfy. Here, the allowable error is ± 20 [nm], more preferably ± 15 [nm], and even more preferably ± 10 [nm]. In that case, what is necessary is just to change the value of the right side of Formula (3) and Formula (4).

であるから、ｎ，ｍはそれぞれ、

である。 Looking FIG 6 (a) and (b), it can be seen that the thickness _{t 2} indicated by hatching reflectance in the vicinity of 450 [nm] R, shows the luminance L are both high values. in this case,

Therefore, n and m are respectively

It is.

Further, in FIG. 6 (c), a change in the color of the light emitted pixels 520 (R) is, as a chromaticity change amount Δx with respect to the reference value in the x-coordinate values in CIExy chromaticity diagram, shown relative thickness _{t 2} It is a graph. Generally it shows stronger red and x value is large, with a layer thickness t ₂ is around 450 [nm] indicated by hatching, it can be seen that there is no big change in color.

において、層厚ｔ_２が４５０［ｎｍ］と一致した値を示すことがわかる。 Figure 7 is a table reflectivity R and the luminance L showed thickness t ₂ which indicates the maximum values for various n, m. As indicated by the thick frame in the table,

It can be seen that the layer thickness t ₂ shows a value consistent with 450 [nm].

においても、層厚ｔ_２が１３５０［ｎｍ］と一致した値を示し、反射率Ｒ及び輝度Ｌを共に高い値にすることができることがわかる。 In addition, as indicated by the bold line in the table,

In FIG. 5, the layer thickness t ₂ shows a value consistent with 1350 [nm], and it can be seen that both the reflectance R and the luminance L can be increased.

Although n and m satisfying the formula (3) exist even for a thicker layer thickness t ₂ , when the layer thickness t ₂ is increased, it takes time to stack the electroluminescent layer 523 (R), which increases the manufacturing cost. There is a risk of inviting.

In the present embodiment, the thickness of the electroluminescent layer 523 (R) of the pixel 520 (R) that emits red light adjacent to the pixel 520 (B) that emits blue light is set to a specific value. In general, in the current electroluminescence display device, the luminance of the blue light is lower than the luminance of the red light and the green light. This is because the reflectance of blue light is relatively high due to material characteristics. However, the combination of pixel colors is not limited to this. For example, to increase the reflectance of the light emitted from the pixels 520 (R), may further define a thickness t ₁ of the electroluminescent layer 523 (B), also in combination with the pixel for emitting green light The thickness of the electroluminescent layer 523 may be determined. Further, not only a combination of colors based on the three primary colors of red, green, and blue, but also an electroluminescence display device using other colors may be used.

  In this embodiment, the shape of the reflective layer 521 is not limited, but it is natural that the structure of the reflective layer 521 described in the first to fourth embodiments may be adopted.

It is a schematic cross section which shows the structure of the electroluminescent display apparatus which concerns on 1st Embodiment. It is a schematic cross section which shows the structure of the electroluminescent display apparatus which concerns on 2nd Embodiment. It is a schematic cross section which shows the structure of the electroluminescent display apparatus which concerns on 3rd Embodiment. It is a schematic cross section which shows the structure of the electroluminescent display apparatus which concerns on 4th Embodiment. It is a schematic cross section which shows partially the structure of the electroluminescent display apparatus which concerns on 5th Embodiment. It is a figure which shows the relationship between the layer thickness of an electroluminescent layer, and a reflectance, a brightness | luminance, and chromaticity change. It is the table | surface which showed the layer thickness in which the reflectance R and the brightness | luminance L show the maximum value with respect to various n and m. It is a schematic cross section which shows the structure of the conventional electroluminescent display apparatus. It is a graph which shows the reflectance of the light in the electroluminescent layer in a red pixel.

Explanation of symbols

  100, 200, 300, 400, 500, 800 Electroluminescence display device, 101, 401, 801 Substrate, 102, 802 Gate insulating layer, 103, 803 Interlayer insulating layer, 104, 804 Protective layer, 105, 205, 305, 505, 805 Pixel separation layer, 106, 506 Flattening layer, 110, 810 TFT, 111, 811 channel, 112, 812 Gate electrode, 113, 813 Source electrode, 114, 814 Drain electrode, 120, 520, 820 pixel, 121 , 221, 321, 421, 521 Reflective layer, 122, 222, 522, 822 Lower electrode, 123, 523, 823 Electroluminescent layer, 124, 424, 524, 824 Upper electrode, 125, 225 Intermediate electrode, 126, 226 In-pixel reflective layer, 12 , 227, 327, 427 Out-of-pixel reflective layer, 130, 530, 830 Sealing substrate, 131, 831 Circularly polarizing reflector, 132, 832 1/4 wavelength plate, 133,833 Linearly polarizing plate, 134,834 Circularly polarizing plate 135, 535, 835 Polarizing member, 140, 540, 840 Space, 821 Reflective electrode.

Claims (12)

A substrate,
A plurality of pixels formed on one surface of the substrate and having a reflective layer, a lower surface electrode, an electroluminescent layer, and an upper surface electrode;
A circularly polarized light reflecting plate disposed opposite to the pixel and transmitting circularly polarized light in one direction and reflecting circularly polarized light in the opposite direction, and linearly polarized light and circularly polarized light are mutually converted. A polarizing member having a circularly polarizing plate;
Have
The reflective layer is
An in-pixel reflective layer disposed at a position corresponding to a region where the lower surface electrode and the electroluminescent layer are in contact with each other;
An out-pixel reflection layer disposed outside a position corresponding to a region where the lower surface electrode and the electroluminescent layer are in contact with each other;
An electroluminescent display device. The electroluminescent display device according to claim 1, wherein the reflective layer is formed by integrally forming the intra-pixel reflective layer and the extra-pixel reflective layer. 3. The electroluminescent display device according to claim 2, wherein the extra-pixel reflective layer is not electrically connected to a member other than the lower surface electrode. The electroluminescent display device according to claim 1, wherein the reflective layer is formed by separately forming the intra-pixel reflective layer and the extra-pixel reflective layer. The electroluminescent display device according to claim 4, wherein the extra-pixel reflective layer is formed on the same surface as the surface on which the intra-pixel reflective layer is formed. The electroluminescent display device according to claim 4, wherein the extra-pixel reflection layer is exposed on an upper surface of the pixel. The electroluminescent display device according to claim 6, wherein the extra-pixel reflective layer is formed on an upper surface of the upper electrode. The electroluminescent display device according to claim 1, wherein the reflective layer includes at least one component selected from silver, aluminum, rhodium, iron, nickel, and chromium. The electroluminescent display device according to claim 1, wherein a pixel separation layer having an extinction coefficient of 0.15 or less with respect to visible light is provided between the plurality of pixels. A substrate,
A plurality of pixels formed on one surface of the substrate and having a reflective layer, a lower surface electrode, an electroluminescent layer, and an upper surface electrode;
A circularly polarized light reflecting plate disposed opposite to the pixel and transmitting circularly polarized light in one direction and reflecting circularly polarized light in the opposite direction, and linearly polarized light and circularly polarized light are mutually converted. A polarizing member having a circularly polarizing plate;
Have
The thickness of the electroluminescent layer in another pixel adjacent to one pixel is
A reflectance at the other pixel of light emitted by the one pixel that changes in accordance with a change in thickness of the electroluminescent layer at the other pixel;
The brightness of light emitted by the other pixel that changes in accordance with a change in the thickness of the electroluminescence layer in the other pixel,
An electroluminescence display device having a peak thickness. The thickness t ₂ of the electroluminescent layer in the other pixel is λ _{1 as} the main wavelength of light emitted from the one pixel, and λ ₂ , n, m as the main wavelength of light emitted from the other pixel, respectively. When it is a positive natural number,

N and m satisfying

The electroluminescent display device according to claim 10, wherein The one pixel is a pixel emitting blue light,
The other pixels are pixels that emit red light,
N and m are

Or

12. The electroluminescent display device according to claim 11, wherein the electroluminescent display device is any one of the above.

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