JP2011003339A - Organic el device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that, in an organic EL element using PEDOT for a hole injection layer constituting the element, current diffuses and flows outside an area at a peripheral part of an area where two electrodes are overlapped with each other in plane due to low resistance of the PEDOT, so that an emission area tends to be spread toward outside from the periphery part of the area where the two electrodes are overlapped with each other in plane.SOLUTION: Light emitted from the organic EL element is made resonated and transmitted by an opening KD formed on a metal film 20. Therefore, heat generated by the light-emitting organic EL element can be dissipated by the metal film 20 with high thermal conductivity, and emission light of the organic EL element can be irradiated as light of an area of a desired size by the opening KD formed smaller than an emission area of the organic EL element.

Description

  The present invention relates to an organic EL device and an electronic apparatus including the organic EL device.

  In recent years, organic electroluminescence (EL) elements are often used as light-emitting elements that are thin and have high luminous efficiency, for example, in optical heads for writing latent images in electrophotographic printers and display devices for displaying images. It has come to be. As is well known, an organic EL element emits emitted light from a light emitting layer while generating heat by passing a current through the light emitting layer formed of a light emitting material. Heat is also generated from the drive circuit that drives the organic EL element to emit light. For this reason, there exists a subject that deterioration of an organic EL element is accelerated by the influence of this generated heat.

  Therefore, a technique for radiating the heat generated in this way has been proposed in the past. For example, Patent Document 1 discloses one technique. In Patent Document 1, a heat conduction plate having holes is joined to the substrate surface opposite to the surface on which the organic EL elements are formed, and the emitted light of the organic EL elements is taken out from the holes, and the heat conduction plate It is intended to dissipate heat.

Japanese Patent Laid-Open No. 2001-237063

  By the way, the organic EL element has a configuration in which an organic layer including a light emitting layer is sandwiched between two electrodes (anode and cathode), and the light emitting region is a region where current flows in the light emitting layer, that is, approximately two electrodes are provided. It becomes the area | region which overlaps planarly. However, in the organic EL element using PEDOT (conductive polymer) for the hole injection layer constituting the organic EL element, due to the low resistance of PEDOT, in the peripheral part of the region where the two electrodes overlap in a plane The current diffuses out of the region and flows. For this reason, the light emitting region spreads from the peripheral portion of the region where the two electrodes overlap in plan view to the outside of the region.

  When such an organic EL element is used as, for example, a light source for an optical head of a printer that forms a latent image on a photosensitive drum, the directivity of emitted light is reduced due to the spread of the light emitting region, and thus formed. The latent image will be blurred or blurred. As a result, there arises a problem that a latent image (image) cannot be formed correctly.

  In order to avoid this, in consideration of the spread of the light emitting region, it can be considered that the planar overlapping region of the two electrodes is previously reduced to reduce the light emitting region. However, when the light emitting region is made smaller than the initial target area in this way, the brightness of the peripheral portion of the actual light emitting region is higher than the brightness of the center of the region where the two electrodes overlap or the portion near the center. Since it becomes dark, the luminance is reduced in the actual light emitting region of the organic EL element. For this reason, in order to make the amount of light extracted in the actual light emitting region the same, it is necessary to cause the organic EL element to emit light brighter than the original brightness. As a result, there is a risk of accelerating the deterioration of the organic EL element in addition to the deterioration due to heat generation, such as shortening the light emission lifetime due to an increase in the load related to the light emission of the organic EL element.

  In addition, although the said patent document 1 has the indication about suppressing degradation by heat_generation | fever, there is no indication about the subject with respect to the breadth of the light emission area | region mentioned above, Therefore, also the solution technique about these subjects is also disclosed at all. It has not been.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following application examples.

  Application Example 1 An organic EL device in which an organic EL element is formed on one surface of a substrate, wherein the substrate surface opposite to the surface on which the organic EL element is formed has a thermal conductivity higher than that of the substrate. A metal film having a high height is provided, and an opening for transmitting light emitted from the organic EL element is formed in the metal film so as to have a small area in a plane with respect to the light emitting area of the organic EL element. It is characterized by being.

  According to this configuration, the light emitted from the organic EL element and the light transmitted through the substrate are transmitted only through the opening of the metal film formed corresponding to the organic EL element. Therefore, the metal film having high thermal conductivity can dissipate heat generated by the organic EL element that emits light, and the light emitted from the organic EL element is made smaller than the actual light emitting region of the organic EL element, for example. The opening can be transmitted as light having a desired area area.

  Application Example 2 In the organic EL device, light emitted from the organic EL element is emitted from at least the opening of the metal film on the substrate surface opposite to the surface on which the organic EL element is formed. A semi-transmissive reflective film that partially reflects and partially transmits is provided.

  According to this configuration, the light emitted from the organic EL element can resonate between the cathode constituting the organic EL element and the transflective film. As a result, the light transmitted through the opening can be made light with high luminance by making the light having a desired wavelength resonate. Further, the directivity of the emitted light can be increased by resonance, and the emitted light can be emitted in a direction perpendicular to the substrate surface, for example. Therefore, for example, it is effective when an organic EL device is used as an optical head.

  Application Example 3 In the organic EL device, the metal film is provided so as to continue to an end portion of the substrate.

  According to this configuration, for example, heat generated by the organic EL element that emits light can be radiated from the end portion of the substrate, so that a heat dissipation structure can be configured without disturbing the light emitting region.

  Application Example 4 In the organic EL device described above, a plurality of the light emitting regions are formed, and all the openings have the same shape.

  According to this configuration, even if there is a variation in the light emitting region of the organic EL element, all the light emitting regions can be adjusted to the same size by the opening.

  Application Example 5 In the organic EL device described above, a plurality of the light emitting regions are formed, and each of the light emitting regions emits light in one of at least two light emitting colors different in color between the light emitting regions, The opening has the same shape for each of the emission colors.

  According to this configuration, the size and shape of the light emitting region can be adjusted by the opening according to the light emission color of the organic EL element. Therefore, for example, when the light emission luminance of the organic EL element varies depending on the light emission color, the luminance between the light emission colors can be adjusted to be the same depending on the size of the opening.

  Application Example 6 Electronic equipment including the organic EL device.

  According to this configuration, an electronic apparatus including an organic EL device having good heat dissipation performance and having a light emitting region having a desired size can be obtained. Therefore, for example, when the electronic device is an electrophotographic printer and the organic EL device is used as an optical head, a latent image (image) in which blurring or blurring is suppressed can be formed, and the optical head A printer in which deterioration is suppressed can be provided.

1 is a schematic configuration diagram of a printer including an organic EL device according to an embodiment of the present invention. Explanatory drawing which showed a mode that the light-emission light of the organic EL element formed in the organic EL apparatus irradiated on a photosensitive drum. (A) is a top view of the organic electroluminescent apparatus of a present Example, (b) is sectional drawing. The explanatory view which showed the field relation of an actual luminescence field and an opening two-dimensionally about an organic EL element. The top view which showed a part of organic electroluminescent apparatus of the 1st modification. Sectional drawing of the organic electroluminescent apparatus of the 1st modification. The top view which showed a part of organic EL apparatus of the 2nd modification.

(Electronics)
The present invention will be described based on examples. FIG. 1 is an explanatory diagram showing a schematic configuration of an electrophotographic printer 1000 as an electronic apparatus including an organic EL device 100 according to an embodiment to which the present invention is applied. In FIG. 1, only the configuration relating to latent image formation is shown, and illustrations of the paper feed mechanism and other mechanisms relating to toner supply, fixing, and development of the other printer 1000 are omitted. Further, the drawings used in the description of the present embodiment including FIG. 1 may be exaggerated as necessary for the description, and needless to say, they do not necessarily indicate the actual size or length. Yes.

  The organic EL device 100 of this embodiment uses an organic electroluminescence (EL) element as a light emitting element, and a plurality of the organic EL elements are arranged in a line in one direction (the direction of the rotation axis of the photosensitive drum). It is. As is well known, an organic EL element is a light-emitting element that emits light by flowing current between two electrodes (anode and cathode) and can be thinned with low power consumption. For this reason, the organic EL device 100 in which the organic EL elements are arranged in a line in this way is a line head that emits light for writing a latent image (image) on the photosensitive drum in the electrophotographic printer 1000 (hereinafter, “ It can be used as an “optical head”. Specifically, as shown in the drawing, light (arrow in the figure) emitted from each organic EL element (not shown) and transmitted through an opening KD described later is a SELFOC (registered trademark) lens array (hereinafter referred to as “SLA”). The latent image is formed by neutralizing the charge charged on the photosensitive drum through the irradiation of the photosensitive drum through the abbreviation. As described above, the organic EL device 100 is configured to be used as an optical head of the printer 1000.

  In the present embodiment, for simplicity of explanation, as shown in FIG. 1, the organic EL device 100 is assumed to have twelve light emitting elements arranged in parallel in one direction (left and right direction in the drawing). Of course, in practice, several hundred to a thousand light emitting elements are arranged in parallel to form an optical head. Further, the light emitting element rows may be a plurality of rows instead of a single row. In the case of a plurality of rows, the organic EL elements may be arranged in a zigzag manner in which the rows are arranged with a half-pitch shift between the rows.

  When the organic EL device 100 is used as an optical head, a current for driving to emit light may be supplied to each organic EL element according to image data. For this reason, the image data and the power source are used to generate a signal that determines the current to be passed through each organic EL element by a control circuit configured by a control IC, an electric element, or the like formed on the circuit board. Applied to the organic EL device 100. In the organic EL device 100, a drive circuit is formed so that a current corresponding to image data is caused to flow through the organic EL element by an applied signal. Thus, the current flowing through the organic EL element is controlled to have a desired light emission amount, and an image (latent image) is formed on the photosensitive drum.

  The flexible substrate is connected (also referred to as “mounting”) to the organic EL device 100 by soldering or a connector (not shown). The flexible board and the control circuit are also connected by soldering or a connector (not shown).

  In the printer 1000 of this embodiment, the configuration of the organic EL device 100 is devised so that a latent image can be correctly formed on the photosensitive drum. The contents of this device will be described first with reference to FIG. 2 in order to facilitate understanding of the description of the configuration of the organic EL device 100 described later.

  FIG. 2 is an explanatory view showing a state in which light emitted from the organic EL element formed in the organic EL device 100 passes through the SLA and is irradiated onto the photosensitive drum. As described above, the actual light emitting area is enlarged as indicated by the broken line in the figure, and the light emitted from the peripheral part of the actual light emitting area has a lower luminance than the central part. Therefore, the actual irradiation area that is irradiated with the light that passes through the SLA and irradiates the photosensitive drum is larger than the desired irradiation area, and the surrounding area has a low luminance. For this reason, the latent image (image) formed on the photosensitive drum is blurred or blurred.

  Therefore, in the present embodiment, the actual light emitting region so that the light of the region portion (shaded portion in the drawing) of the opening KD having a region area smaller than the actual light emitting region of the organic EL element is incident on the SLA. The light emitted from the light-emitting area having a low luminance in the peripheral portion is blocked. By doing so, light from the enlarged light emitting region can be cut, and blurring and blurring occurring in the formed latent image can be suppressed.

  Furthermore, in this embodiment, as indicated by the white arrow in the figure, the directivity is given to the light incident on the SLA from the opening KD. By doing so, the light incident on the SLA in the vertical direction is irradiated to the photosensitive drum without being dispersed while maintaining the directionality thereof. At this time, by forming the opening KD so as to have a desired irradiation area, a latent image (image) corresponding to the image data is formed on the photosensitive drum in a state where blur and blurring are suppressed. It can be formed correctly.

(Organic EL device)
Now, the organic EL device 100 of this embodiment will be described with reference to FIG. FIG. 3A is a plan view of the organic EL device 100 viewed from the direction in which the light emitted from the organic EL element is emitted, and FIG. 3B is along the line AA in FIG. 2 is a cross-sectional view of the organic EL device 100. FIG.

  As shown in FIG. 3A, the organic EL device 100 of this embodiment includes a plurality of organic EL elements (not shown) and a drive circuit for driving each organic EL element to emit light. The organic EL device 100 according to the present embodiment is a so-called bottom emission method, in which an organic EL element that emits a single color (for example, red) is formed. That is, as shown in FIG. 3B, the anode 30 and at least the hole injection layer and the light emitting layer are formed on one surface of the substrate 10 made of a light-transmitting material (for example, glass or resin material). The organic layer 40 containing and the cathode 50 are laminated | stacked in order, and the organic EL element is formed. And an electric current flows into the organic layer 40 (light emitting layer) pinched | interposed into the area | region part which the anode 30 and the cathode 50 overlap in a plane, and the organic layer 40 light-emits. Therefore, in the organic EL device 100, the region of the anode 30 is approximately a light emitting region. The light emitting area will be further described later.

  The anode 30 is made of a conductive material (for example, ITO) that transmits light emitted from the organic EL element. The organic layer 40 is made of a conductive polymer (for example, PEDOT) as a hole injection layer, and is formed by a coating film forming method such as a spin coating method or an ink jet method. Therefore, the resistance value of the hole injection layer is generally lower than that of an organic material used as a light emitting layer. The cathode 50 is made of a conductive material (for example, aluminum) having a thickness (for example, 300 nm) that exhibits a reflection function for reflecting light emitted from the organic EL element. In this embodiment, a calcium (Ca) layer (for example, 5 nm) may be formed between the cathode 50 and the organic layer 40 to reduce the electron injection barrier to the organic layer 40.

  Although explanation of the structure is omitted, the surface of the organic EL element having such a configuration is sealed with an inorganic film, glass, or metal in order to ensure reliability.

  Further, in the organic EL device 100 of the present embodiment, as shown in FIG. 3B, the substrate 10 has a surface on which the emitted light of the organic EL element is emitted, that is, a surface on which the organic EL element is formed. A transflective film 60 that partially reflects and partially transmits the emitted light of the organic EL element is provided on the opposite substrate surface side. Further, on the transflective film 60, the metal film 20 having an opening KD provided in accordance with each organic EL element is formed. As shown in FIG. 3A, the metal film 20 is formed so as to extend to the end portion of the substrate 10 and is formed so as to cover almost the entire surface of the substrate 10 in this embodiment.

  In the present embodiment, the transflective film 60 may be formed by forming a thin film of a light reflective metal (for example, aluminum) on the substrate 10 by sputtering or vapor deposition. Alternatively, a metal oxide can be used as the transflective film 60.

  The metal film 20 is a semi-transmissive reflective film having a predetermined thickness according to the amount of heat radiated from a metal material (for example, aluminum or chromium) having light shielding properties and higher thermal conductivity than the substrate 10 by a method such as mask vapor deposition. It is formed by laminating on 60. At this time, an opening KD having a predetermined shape (for example, a circle having a diameter of 50 μm or less) is formed in the metal film 20. As a matter of course, the formed opening KD only needs to have a shape of an irradiation region suitable as an optical head in order to form a latent image on which blur and blurring are suppressed on the photosensitive drum, as described above, and is not necessarily circular. It is not limited to. For example, an ellipse or a rectangle may be used.

  Now, as shown in FIG. 3B, the organic EL device 100 of the present embodiment having such a configuration transmits light (here, red light) emitted from the organic layer 40 semi-transparently with the cathode 50. Resonance with the reflective film 60 can be achieved. That is, for example, when the phase change due to reflection is not considered, the optical distance (a value obtained by multiplying the physical distance by the refractive index) between the cathode 50 and the semi-transmissive reflective film 60 is set to half of the red wavelength. By adjusting the value to an integer multiple, the cathode 50 and the transflective film 60 can resonate as shown in the figure. As a result, the light emitted from the organic EL element and emitted through the opening KD becomes light having directivity in which the optical axes are aligned in the direction perpendicular to the reflection surface, that is, the surface of the substrate 10.

  The organic EL device 100 according to the present embodiment uses the opening KD formed in the metal film 20 to shield the light in the peripheral portion of the actual light emitting region formed by the light emitted from the organic layer 40. Light having a higher directivity due to resonance with the transflective film 60 (the white arrow in FIG. 3B) can be emitted to the SLA.

  Here, the region of the opening KD formed in the metal film 20 will be supplementarily described with reference to FIG. FIG. 4 is an explanatory view showing the area relationship between the actual light emitting area and the opening KD in plan for one organic EL element.

  As shown in the drawing, the light emitting region of the organic EL element is basically an overlapping region of electrodes in which two electrodes of the anode 30 and the cathode 50 overlap in a plane. However, since the hole injection layer has a low resistance in the outer peripheral area AR2 in the electrode overlapping area, the current flowing from the anode 30 to the cathode 50 is between the cathode 50 existing outside the electrode overlapping area. May cause a diffusion phenomenon. For this reason, in the outer peripheral area AR2 in the overlapping area of the electrodes, the current density is lower than that in the central area, and the luminance is lowered. Then, due to the current flowing outside the electrode overlapping region, the light emitting region AR3 expands outside the electrode overlapping region to form an actual light emitting region. Of course, since the current in the light emitting area AR3 decreases as the area expands, the luminance gradually decreases in the area expansion direction.

  On the other hand, as described above, of the emitted light in the light emitting region, the light traveling in the direction perpendicular to the substrate surface of the substrate 10 resonates between the cathode 50 and the transflective film 60 and the directivity is enhanced. Resonant light. It may be considered that the area AR1 where the resonance light exists is present in the overlapping area of the electrodes. This is because it may be considered that a large amount of light traveling in the direction perpendicular to the substrate 10 is present in the overlapping region of the electrodes. In the region where the resonance light exists, the luminance is also made uniform.

  Therefore, in the present embodiment, the opening KD is formed so as to be approximately coincident with the area AR1 for emitting light with uniform luminance and enhanced directivity. Therefore, the opening KD has a small area in a plane with respect to the light emitting area (actual light emitting area). At this time, if the region of the opening KD is made to coincide with the region desired for forming the latent image, the opening can be obtained even when the actual light emitting region of the organic EL element is larger than the desired size. It can be adjusted to a desired size by the part KD.

  For example, when the region where the organic EL element is formed on the substrate 10 is limited, the size of the region AR1 is limited. Therefore, the size of the light emitting region desired for forming the latent image is smaller than that of the region AR1. May be relatively large. In such a case, the region of the opening KD is an electrode overlapping region or a region larger than the electrode overlapping region, but by making the region at least smaller than the actual light emitting region, the light emitted from the organic EL element can be reduced. It is possible to transmit light having a desired area area in which the luminance difference is suppressed.

  In addition, in the plurality of organic EL elements formed in the organic EL device 100, there are not a few manufacturing variations in the functional layers constituting the organic EL element, such as the formation position and size of the anode 30, for example. Therefore, due to variations in these functional layers, for example, a plurality of organic EL elements to be formed may have different sizes of light emitting regions.

  Therefore, although not shown, in this embodiment, in such a case, it is preferable to form all the openings KD so as to have the same shape. In this way, even if there is a variation in the light emitting region of the organic EL element, all the light emitting regions can be adjusted to the same size by the opening KD. Therefore, when the organic EL device 100 of this embodiment is used for an optical head, the entire photosensitive drum can be exposed in the same irradiation region.

  In addition, as described above, the metal film 20 is formed so as to extend to the end of the substrate 10. In this embodiment, as shown in FIG. 3A, the substrate 10 is formed so as to cover almost the entire surface. Therefore, although not shown, when the printer 1000 has a structure in which the SLA is attached to the organic EL device 100 with an adhesive, a heat sink (not shown) is brought into contact with, for example, the metal film 20 at the end of the substrate 10 that does not interfere with the SLA. Can be arranged. As a result, the heat generated in the organic EL device 100 and absorbed by the metal film 20 can be radiated.

  As described above with reference to FIGS. 3 and 4, the organic EL device 100 according to the present embodiment transmits light emitted from the organic EL element only in the region of the opening KD formed in the metal film 20. Therefore, the metal film 20 having high thermal conductivity can dissipate heat generated by the organic EL element that emits light, and the light emitted from the organic EL element is formed according to, for example, the light emitting region of the organic EL element. The portion KD can be emitted as light having a desired area area.

  Further, the light emitted from the organic EL element can resonate with light having a desired wavelength between the cathode 50 and the semi-transmissive reflective film 60 constituting the organic EL element, for example. As a result, the light emitted from the organic EL element that passes through the opening KD can be light having a desired wavelength and having directivity in the direction perpendicular to the substrate surface. Accordingly, when the organic EL device is used as an optical head, it can be expected that the latent image to be formed is prevented from being blurred or blurred. Further, it can be expected that the luminance of the emitted light emitted from the opening KD is increased by resonance.

  Although the present invention has been described using one embodiment as described above, the present invention is not limited to such an embodiment and can be implemented in various forms without departing from the spirit of the present invention. Of course. Hereinafter, a modification will be described.

(First modification)
In the above embodiment, the organic EL device is used as an optical head in which organic EL elements are arranged in one direction. However, the present invention is not limited to this, and the organic EL device is used as a display panel arranged in one direction. May be. At this time, since it is used as a display panel, in the present modification, unlike the above embodiments, the light emission colors of the light emitting regions of the respective organic EL elements may emit a plurality of colors having different colors between the light emitting regions. Good. Furthermore, it is preferable that the opening KD formed corresponding to each organic EL element has a shape in which the size of the light emitting region is different for each emission color that emits the same color among the plurality of emission colors. This modification will be described with reference to FIG. FIG. 5 is a plan view showing a part of the organic EL device 100a of the present modification.

  As shown in the drawing, in the organic EL device 100a of this modification, the light emitting regions of the organic EL elements emit light of R (red), G (green), and B (blue) in order in the arrangement direction. It is configured. The metal film 20 has all the openings KD corresponding to the organic EL elements that emit light of R color in a circular shape having a diameter D1, and the openings KD that correspond to the organic EL elements that emit light of G color. All are formed in a circular shape with a diameter D2, and all the openings KD corresponding to the organic EL elements that emit B color are formed in a circular shape with a diameter D3.

  In this modification, each opening KD is formed so as to satisfy the diameter D2 <diameter D1 <diameter D3. This is based on the assumption that, for example, the G color emits the brightest light and the B color emits the darkest light due to the difference in the light emission characteristics of each organic EL element, and the size of the area of the opening KD. Thus, the light quantity of each color is corrected to make the luminance of the R, G, and B light uniform. Of course, the size (diameter) of each opening KD may be determined according to the light emission luminance of each light emitting region. In this modification, the opening KD is circular, but the opening KD is not necessarily limited to a circular shape as long as the organic EL device 100a can be used as a display panel. In particular, in the case of an organic EL device configured such that three organic EL elements that emit R, G, and B colors function as one pixel, the shape of the opening KD is preferably an ellipse or a rectangle.

  As described above, according to this modification, the size and shape of the light emitting region can be adjusted by the opening according to the light emission color of the organic EL element. Therefore, for example, when the light emission luminance varies depending on the light emission color, the luminance can be adjusted to be the same depending on the size of the light emission region.

  Furthermore, in this modification, the aperture of each organic EL element is adjusted by adjusting the wavelength of light resonating between the cathode 50 and the transflective film 60 to the R, G, and B colors. The light emitted from the organic EL element that passes through the portion KD is light having directivity in the direction perpendicular to the substrate surface for all of the R, G, and B colors. An example of this will be described with reference to FIG. FIG. 6 is a cross-sectional view of the organic EL device 100a taken along line CC in FIG.

  Unlike the organic EL device 100 of the above embodiment, the organic EL device 100a of the present modification is formed with organic EL elements that emit light of different colors (here, R color, G color, and B color). That is, as illustrated, the organic EL element is an organic layer including at least a hole injection layer and a light emitting layer on one surface of a substrate 10a made of a light-transmitting material (for example, glass or resin material). The organic layer 40R that emits R color, the organic layer 40G that emits G color, the organic layer 40B that emits B color, and the anode 30 are formed in a region partitioned by a partition made of a resin material. ing. Then, the cathode 50 is formed so as to cover the organic layers 40R, 40G, and 40B and the whole partition wall, and an organic EL element is formed.

  The organic EL element of this modification is formed by a coating method (for example, an ink jet method or a spin coating method) as in the above-described embodiment. For example, the hole injection layer is formed by applying the PEDOT / PSS dispersion liquid to the region partitioned by the partition walls, followed by drying and baking. The light-emitting layer is formed by applying a light-emitting material to a region partitioned by the partition walls and drying after forming the hole injection layer.

  On the other hand, as shown in the drawing, an opening KD corresponding to the organic EL element having the organic layer 40G and the organic layer 40B are provided on the substrate surface opposite to the one surface of the substrate 10a on which the organic EL element is formed. A recess is formed corresponding to each region of the opening KD corresponding to the organic EL element. The concave portion can be formed by an etching method using a resist mask or a mechanical processing method.

  Then, a semi-transmissive reflective film 60 is provided on the substrate surface of the substrate 10a where the recesses are formed, as in the above embodiment, and further provided on the semi-transmissive reflective film 60 according to each organic EL element. A metal film 20 having an opening KD is formed.

  In the organic EL device 100a of the present modified example configured as described above, the wavelengths of light resonating between the cathode 50 and the semi-transmissive reflective film 60 are respectively set to R color and G in the opening KD of each organic EL element. It can be adjusted to light of color and B color. That is, the thickness of the substrate 10a is set so that an optical distance at which the R-color light resonates between the cathode 50 and the transflective film 60 can be obtained in the opening KD corresponding to the organic EL element having the organic layer 40R. Decide. Next, in the opening KD corresponding to the organic EL element having the organic layer 40G, a recess formed in the substrate 10a so as to obtain an optical distance at which the G color light resonates between the cathode 50 and the transflective film 60. Determine the depth of the. Similarly, in the opening KD corresponding to the organic EL element having the organic layer 40B, a recess formed in the substrate 10a so as to obtain an optical distance at which B color light resonates between the cathode 50 and the transflective film 60. Determine the depth of the. Then, a resist mask is created as a half mask that provides an etching amount corresponding to a determined depth of the recess, for example, and the substrate 10a is etched using the created resist mask. By doing so, the emitted light of the organic EL element that passes through the opening KD becomes light that resonates for all of the R color, G color, and B color. As a result, R-color light, G-color light, and B-color light having directivity in a direction substantially perpendicular to the substrate surface is emitted from each opening.

  As the transflective film 60, a film in which a light-reflective metal (for example, aluminum) is formed on the substrate 10a by a sputtering method or a vapor deposition method as in the above embodiment can be adopted. Alternatively, a metal oxide can be used as the transflective film 60.

  The metal film 20 is shielded by a method such as mask vapor deposition in the same manner as in the above-described embodiment, and a predetermined amount of metal material (for example, aluminum or chromium) having a heat conductivity higher than that of the substrate 10a is determined according to the amount of heat radiated. The thickness is formed on the semi-transmissive reflective film 60. At this time, an opening KD having a predetermined shape (for example, a circle having a diameter of 25 to 40 μm) is formed in the metal film 20 by a mask. Of course, the opening KD to be formed has a shape of an irradiation region desired for forming a latent image on which the blur and blurring are suppressed on the photosensitive drum, as described above.

  In this modification, the structural description is omitted, but the surface of each organic EL element is sealed with an inorganic film, glass, or metal in order to ensure reliability, as in the above embodiment.

(Second modification)
In the first modification, the organic EL device is used as a display panel in which the organic EL elements are arranged in one direction. However, the organic EL device is not limited to this, and the organic EL device is arranged in two directions (matrix) that intersect the organic EL elements. It may be used as a display panel state arranged in (direction). In this case, for example, the arrangement of light emitting elements in one direction (row direction) is sequentially selected with respect to the other direction (column direction), and a current corresponding to each of the selected organic EL elements is passed. Thus, the light emission amount of all the organic EL elements may be controlled. This modification will be described with reference to FIG. FIG. 7 is a plan view showing a part of the organic EL device 100b of this modification.

  As shown in the drawing, the organic EL device 100b according to the present modification includes a metal having an opening KD provided in correspondence with each organic EL element on the surface opposite to the substrate surface on which the organic EL element (not shown) is formed. A film 20b is formed. The opening KD of this modification has an oval shape, and one opening KD is arranged to emit R color light, G color light, and B color light in order in a direction orthogonal to the longitudinal direction of the oval shape. Yes. Therefore, the opening KD is configured to function as one pixel each having three openings KD continuous in a direction orthogonal to the longitudinal direction of the oval shape as sub-pixels.

  Here, in this modification, the openings KD that function as sub-pixels that emit R color are all formed in an oval shape having the same size, and the openings KD that function as sub-pixels that emit G color are all the same. The openings KD that are formed in an oval shape having a size and function as sub-pixels that emit B color are all formed in an oval shape having the same size.

  Also in the organic EL device 100b of this modification, the opening KD is formed in a region smaller than the actual light emitting region of the sub-pixel that emits each color light. As in the first modification, a semi-transmissive reflective film is formed in the opening KD, and a recess having a depth necessary for resonating each color light is formed on the substrate surface. In addition, other structures, such as an organic EL element, are formed with the same structure as the said 1st modification.

  According to this modification, the size and shape of the light emitting region can be adjusted by the opening KD according to the light emission color of the organic EL element. Therefore, for example, when the light emission luminance varies depending on the light emission color, the luminance can be adjusted to be the same depending on the size of the light emission region.

(Other variations)
In the above embodiment and the modification, the semi-transmissive reflective film 60 is provided so that the light resonated from the opening KD is emitted. However, the present invention is not limited to this, and the semi-transmissive reflective film 60 may not be provided. Good. For example, when the light emitted from the opening KD already has directivity in a range suitable for exposure, or when the use of the light emitted from the opening KD does not depend on directivity, the organic EL There is no need to resonate the emitted light of the device.

  In the above-described embodiment, the electronic apparatus equipped with the organic EL device is an electrophotographic printer. However, the present invention is not limited to this. For example, when the organic EL device has a shape as a display panel as in the second modified example, a display device such as a digital camera, a video camera, a television, or a mobile phone is provided as an electronic device on which the organic EL device is mounted. It is preferable to use an electronic device.

  DESCRIPTION OF SYMBOLS 10 ... Substrate, 10a ... Substrate, 20, 20b ... Metal film, 30 ... Anode, 40 ... Organic layer, 40B ... Organic layer, 40G ... Organic layer, 40R ... Organic layer, 50 ... Cathode, 60 ... Transflective film, 100, 100a, 100b ... Organic EL device, 1000 ... Printer, KD ... Opening.

Claims (6)

An organic EL device in which an organic EL element is formed on one surface of a substrate,
A metal film having a higher thermal conductivity than the substrate is provided on the substrate surface opposite to the surface on which the organic EL element is formed,
In the metal film, an opening that transmits light emitted from the organic EL element is formed to have a small area in a plane with respect to the light emitting area of the organic EL element. Organic EL device. The organic EL device according to claim 1,
On the substrate surface opposite to the surface on which the organic EL element is formed, there is a transflective film that partially reflects and partially transmits light emitted by the organic EL element at least in the opening of the metal film. An organic EL device characterized by being provided. The organic EL device according to claim 1, wherein
The organic EL device, wherein the metal film is provided so as to continue to an end of the substrate. An organic EL device according to any one of claims 1 to 3,
A plurality of the light emitting regions are formed,
The organic EL device characterized in that all the openings have the same shape. An organic EL device according to any one of claims 1 to 3,
A plurality of the light emitting regions are formed,
Each of the light emitting regions emits light in one of at least two light emitting colors different in color between the light emitting regions,
The organic EL device, wherein the opening has the same shape for each of the emission colors.   An electronic apparatus comprising the organic EL device according to any one of claims 1 to 5.