JP2005329643A - Collar light emitting element array, and exposure device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate production of a light emitting element array with its color purity improved. <P>SOLUTION: The light emitting element arrays each include a plurality of types of light emitting elements 20 having respective emission spectra which are present in wavelength areas different from each other such that ends of the respective wavelength areas overlap each other, and the light emitting elements 20 are arranged side by side so as to form a red line light emitting element array 6R, a green line light emitting element array 6G, and a blue line light emitting element array 6B, for instance. According to the light emitting element arrays, an optical filter 9 for modifying at least part of ranges of the wavelength areas overlapping each other as attenuated wavelength areas, is inserted in common into an optical path of light 2 emitted from each of the plurality of types of light emitting elements 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color light emitting element array in which a plurality of types of light emitting elements that emit light of different colors are arranged in parallel.

  The present invention also relates to an exposure apparatus for exposing a color photosensitive material using the color light emitting element array as described above.

  Conventionally, as shown in Patent Document 1, for example, there is a color organic EL panel in which a plurality of types of organic EL (electroluminescence) light emitting elements that emit light in different wavelength regions such as red, green, and blue are arranged in parallel. It is publicly known.

  Many of these organic EL panels are configured as a passive matrix drive type. In this case, a plurality of anodes and a plurality of cathodes extending across the anodes are arranged in a state in which the intersecting portions are arranged in a matrix. The organic EL light-emitting elements are formed so as to face each other and intersect each other. That is, one organic EL light emitting element is basically composed of the anode and cathode facing each other and an organic compound layer including a light emitting layer disposed between these electrodes. In this organic EL light emitting device, when a current is passed through the organic compound layer through the anode and the cathode, the light emitting layer emits light having a specific wavelength corresponding to the composition.

  If such an organic EL panel is used, a display device that displays a full-color image can be configured.

  In addition to configuring a display device, this type of organic EL panel is also considered to be used to configure an exposure device that exposes a color photosensitive material as disclosed in, for example, Patent Document 2. The exposure apparatus disclosed in Patent Document 2 performs main scanning with a plurality of organic EL light emitting elements arranged in one direction of the organic EL panel, and relatively moves the organic EL panel and the photosensitive material in a direction substantially perpendicular to this direction. Thus, sub-scanning is performed. In addition, if an organic EL panel in which organic EL light-emitting elements are two-dimensionally arranged in the main scanning direction and the sub-scanning direction is used, the organic EL panel and the photosensitive material are not moved relative to each other. A two-dimensional image can also be exposed.

  By the way, the currently provided color organic EL light emitting elements have a broad emission spectrum and emit light in different wavelength regions such as red, green and blue, and the end portions of the wavelength regions overlap each other. It has become. This point will be described in detail with a specific example. For example, when an organic EL light emitting element that emits green light and an organic EL light emitting element that emits blue light are used, the green light is emitted regardless of which element is driven. Alternatively, blue-green light is emitted mixed with blue light. For this reason, when an organic EL panel composed of this color organic EL light-emitting element is applied to a display device, the color purity is low and the saturation of the display image is low.

  In addition, when an exposure apparatus that exposes a color image from such an organic EL panel is configured, color mixing occurs in the exposed image. In other words, if the organic EL panel mentioned in the above specific example is used for exposure of a positive color photosensitive material having sensitivity in the blue-green region, even if green light is emitted so as to develop a green color, On the contrary, blue may be developed by blue-green light, or on the contrary, even when blue light is irradiated so as to develop blue, green may be developed by blue-green light mixed therewith. This is because the emission spectrum of the organic EL light-emitting element is broad, so that the emission spectrum end of the green light-emitting element overlaps with the spectral sensitivity range end of the blue photosensitive layer. This is caused by overlapping with the end of the spectral sensitivity region of the green photosensitive layer.

Accordingly, various proposals have been made for improving the color purity of the organic EL light emitting device. For example, Patent Document 1 discloses a technique for improving color purity by providing a color filter in the optical path of light emitted from each organic EL light emitting element. Reference 3 discloses a technique in which light emitted from each organic EL light emitting element is passed through a color conversion layer to be converted into light of another desired color with high color purity. Furthermore, it has also been proposed to use the color filter and the color conversion layer together.
JP-A-8-321380 JP 2001-356422 A JP 2003-187975 A

  However, when the above color filter is provided, a complicated photolithography process is required to fractionate and form the color filter of each color for each organic EL light emitting element that becomes one pixel, so that the production yield is low. There is a problem that the cost of the organic EL panel is high. In this case, when a color filter is formed on the surface of the glass of the organic EL panel (the surface opposite to the side on which the organic EL light emitting element is formed), the color filter is in a state where the light has advanced and spread by the thickness of the glass. Therefore, in order to allow only light of a predetermined color to be incident on a color filter of a predetermined color, it is necessary to dispose each organic EL light emitting element to some extent, thereby reducing the pixel density of the organic EL panel. To do. On the other hand, when a color filter is formed on the back side of the glass of the organic EL panel (the surface on the side where the organic EL light emitting element is formed), the transparent electrode of the organic EL light emitting element usually made of ITO and the color filter are in contact with each other. The organic pigment in the filter diffuses into the transparent electrode, which may cause problems such as deterioration in characteristics of the organic EL light emitting element, reduction in element life, and reduction in production yield.

  In addition, the fluorescence of the desired color emitted from the color conversion layer also has a broad emission spectrum. Therefore, even if this color conversion layer is provided, it is difficult to sufficiently increase the color purity.

  In addition, when the color filter and the color conversion layer are used in combination, the same problem as in the case of using each of them alone occurs, and it is difficult to sufficiently increase the color purity.

  Although the problem in the color organic EL panel has been described above, the same problem can naturally occur in a color light emitting element array using a light emitting element having a broad emission spectrum. Furthermore, not only self-luminous light-emitting elements such as organic EL light-emitting elements, but also color light-emitting element arrays using elements composed of combinations of light control elements such as liquid crystal and PLZT and light sources, Similar problems can occur if the spectrum is broad. In the present specification, an element formed by combining the above-described light control element and light source is also included in the “light emitting element”.

  In view of the above circumstances, an object of the present invention is to provide a color light-emitting element array having sufficiently high color purity and easy to manufacture.

  Another object of the present invention is to prevent color mixing of an exposure image in an exposure apparatus using a color light emitting element array.

  The color light emitting device array according to the present invention has a broad emission spectrum as described above, that is, a plurality of types of light emission each having an emission spectrum that is in different wavelength regions and whose end portions overlap each other. In a color light emitting element array in which elements are arranged side by side, an optical filter having at least a part of the overlapping wavelength region as an attenuation wavelength region is commonly used in an optical path of light emitted from the plurality of types of light emitting elements. It is characterized by being inserted.

  In order to simplify the apparatus configuration, it is desirable that only one optical filter is provided in common with respect to the total number of light emitting elements. A total of two can be provided.

  Further, “attenuation” in the attenuation wavelength region does not necessarily mean that the transmittance is 0%, but means that the light in the wavelength region is attenuated to an extent not substantially related to image display or exposure. Generally, the transmittance may be about 0 to 50%. As an optical filter having such characteristics, for example, an optical filter made of a dielectric multilayer film can be suitably used.

  Further, the present invention is applied to an organic EL panel in which the plurality of types of light-emitting elements are organic EL light-emitting elements, particularly preferably three types of organic EL light-emitting elements that emit light in the red, green, and blue wavelength regions, respectively. It is desirable.

On the other hand, the exposure apparatus according to the present invention uses an optical filter similar to the above even when using a color photosensitive material that may cause color mixing when a color light emitting element array having a plurality of light emitting elements having a broad emission spectrum is used. It is designed to prevent color mixing, and more specifically,
A color light-emitting element array in which a plurality of types of light-emitting elements each having an emission spectrum in a different wavelength region are arranged in parallel;
Means for driving the color light emitting element array based on image data;
A photosensitive material that may cause color mixing, that is, a plurality of color photosensitive layers each having spectral sensitivity corresponding to each of the plurality of emission spectra, and at the end of the spectral sensitivity range of one color photosensitive layer. Means for holding a color photosensitive material in which the end of the emission spectrum corresponding to the spectral sensitivity range adjacent to the sensitivity range overlaps;
In an exposure apparatus comprising an imaging lens for forming an image of light emitted from the color light emitting element array on the color photosensitive material,
An optical filter having an attenuation wavelength region in at least a part of the wavelength region where the end of the spectral sensitivity region and the end of the emission spectrum overlap is common to the optical path of the light emitted from the plurality of types of light emitting elements. It is inserted in.

  In the color light emitting element array according to the present invention, an optical filter having an attenuation wavelength region in at least a part of a wavelength region overlapping between a plurality of types of light emitting devices is an optical path of light emitted from the plurality of types of light emitting devices. In this way, the light in the overlapping wavelength region can be cut by the optical filter. In other words, as explained in the above example, blue-green light mixed in green light or blue light can be cut by this optical filter. Thereby, in the color light emitting element array of the present invention, the color purity is sufficiently enhanced.

  The optical filter is not fractionated in units of pixels like the color filter described above, but is provided in common for each color of light, and requires a complicated manufacturing process such as a photolithography process. Therefore, the color light emitting element array according to the present invention has a simple structure and can be manufactured at low cost.

  In addition, when using the above-described color filter fractionated in units of one pixel, the fractionation has been a constraint to narrow the pixel interval, but when using the optical filter, such a constraint is eliminated, It is possible to display or expose a high-definition image with a smaller pixel interval.

  On the other hand, the exposure apparatus according to the present invention has a wavelength region in which the end of the spectral sensitivity range of one color photosensitive layer and the end of the emission spectrum of the light emitting element corresponding to the spectral sensitivity range adjacent to the spectral sensitivity range overlap. When an optical filter having an attenuation wavelength region in at least a part of the range is inserted in the optical path of light emitted from a plurality of types of light emitting elements, light that generates color mixture in this wavelength region is Can be cut with a filter. Thereby, according to this exposure apparatus, it is possible to prevent color mixing in the exposed image.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a partially broken front shape of an exposure apparatus according to an embodiment of the present invention, and FIG. 2 shows a partially broken side shape of the exposure apparatus. As shown in the drawing, this exposure apparatus conveys the exposure head 1 and the color photosensitive material 3 held at the position where the exposure light 2 emitted from the exposure head 1 is irradiated at a constant speed in the direction of arrow Y in FIG. For example, a sub-scanning means 4 such as a nip roller is provided.

  The exposure head 1 is disposed at a position for receiving the organic EL panel 6 and the exposure light 2 emitted from the organic EL panel 6, and has a refractive index for forming an image of the exposure light 2 on the color photosensitive material 3. A distributed lens array 7 and holding means 8 (not shown in FIG. 2) for holding the lens array 7 and the organic EL panel 6 are provided. The gradient index lens array 7 includes two rows of arrays in which a large number of minute gradient index lenses 7 a are arranged in the main scanning direction (arrow X direction) orthogonal to the sub-scanning direction Y. Is.

  The exposure apparatus of this embodiment exposes a color image to the color photosensitive material 3 which is a full-color negative type silver salt photographic photosensitive material as an example, and the organic EL panel 6 constituting the exposure head 1 is arranged in the sub-scanning direction Y. A red line light emitting element array 6R, a green line light emitting element array 6G, and a blue line light emitting element array 6B arranged side by side are provided. Each of the line-shaped light emitting element arrays 6R, 6G, and 6B includes a large number of red organic EL light emitting elements, green organic EL light emitting elements, and blue organic EL light emitting elements arranged in parallel in the main scanning direction X.

  In FIG. 1 and FIG. 2, one of the light emitting elements is typically shown as an organic EL light emitting element 20. Each organic EL light emitting element 20 is formed by sequentially laminating a transparent anode 21, an organic compound layer 22 including a light emitting layer, and a metal cathode 23 on a transparent substrate 10 made of glass or the like. Then, red light emitting elements, green light emitting elements, and blue light emitting elements are respectively applied as the light emitting layers, thereby forming red organic EL light emitting elements, green organic EL light emitting elements, and blue organic EL light emitting elements, respectively.

  The line-shaped light emitting element arrays 6R, 6G, and 6B are driven by the drive circuit 30 shown in FIG. In other words, the drive circuit 30 sets the cathode cathode which is the scanning electrode to be sequentially turned on in a predetermined cycle and the transparent anode 21 which is the signal electrode to be turned on based on the image data D indicating a full color image. The line-shaped light emitting element arrays 6R, 6G and 6B are driven by a so-called passive matrix line sequential selection driving method. The operation of the drive circuit 30 is controlled by a control unit 31 that outputs the image data D.

  Elements constituting each organic EL light emitting element 20 are arranged in a sealing member 25 made of, for example, a stainless steel can. That is, the edge of the sealing member 25 and the transparent substrate 10 are bonded, and the organic EL light emitting element 20 is sealed in the sealing member 25 filled with dry nitrogen gas.

  In the organic EL light emitting device 20 having the above configuration, when a predetermined voltage is applied between the metal cathode 23 and the transparent anode 21 extending across the metal cathode 23, an organic compound is formed at each intersection of the electrodes to which the voltage is applied. A current flows through the layer 22, and the light emitting layer contained therein emits light. The emitted light passes through the transparent anode 21 and the transparent substrate 10 and is emitted as exposure light 2 to the outside of the device. An optical filter 9 is attached to the lower surface of the transparent substrate 10, and all the exposure light 2 from the line light emitting element arrays 6R, 6G, and 6B is transmitted through the optical filter 9 and emitted. The filter 9 will be described in detail later.

  Here, the transparent anode 21 preferably has a light transmittance of at least 50 percent or more, preferably 70 percent or more, in the visible light wavelength region of 400 nm to 700 nm. As the material of the transparent anode 21, conventionally known compounds such as tin oxide, indium tin oxide (ITO), and zinc indium oxide can be used as appropriate, but other metals having a high work function such as gold and platinum. You may use the thin film which consists of. In addition, organic compounds such as polyaniline, polythiophene, polypyrrole, or derivatives thereof can also be used. Supervised by Yutaka Sawada, “New Development of Transparent Conductive Film”, published by CMC Co., Ltd. (1999), there is a detailed description of the transparent conductive film, and what is shown there can be applied to the present invention. It is. The transparent anode 21 can be formed on the transparent substrate 10 by a vacuum deposition method, a sputtering method, an ion plating method, or the like.

  On the other hand, the organic compound layer 22 may have a single-layer structure composed of only a light emitting layer, or other layers such as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer in addition to the light emitting layer. A stacked structure may be used as appropriate. Specific layer structures of the organic compound layer 22 and the electrode include an anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode structure, and an anode / light emitting layer / electron transport layer / cathode, anode. / Hole transport layer / light-emitting layer / electron transport layer / cathode and the like. A plurality of light emitting layers, hole transport layers, hole injection layers, and electron injection layers may be provided.

  The metal cathode 23 is formed of a metal material such as an alkali metal such as Li or K having a low work function, an alkaline earth metal such as Mg or Ca, and an alloy or a mixture of these metals with Ag or Al. Is preferred. In order to achieve both storage stability and electron injectability at the cathode, the electrode formed of the above material may be further coated with Ag, Al, Au, or the like having a high work function and high conductivity. Note that, similarly to the transparent anode 21, the metal cathode 23 can also be formed by a known method such as a vacuum deposition method, a sputtering method, or an ion plating method.

  The operation of the exposure apparatus having the above configuration will be described below. Here, the number of pixels in the main scanning direction of the line-shaped light emitting element arrays 6R, 6G, and 6B, that is, the number of the parallel arrangement of the transparent anodes 21 is n. When the color photosensitive material 3 is subjected to image exposure, the color photosensitive material 3 is conveyed by the sub-scanning means 4 at a constant speed in the arrow Y direction. In synchronism with the conveyance of the color photosensitive material 3, one of the three metal cathodes 23 is sequentially turned on by the cathode driver of the drive circuit 30 described above.

  In this manner, the anode driver of the drive circuit 30 is in the first, second, third,... Within the period when the first metal cathode 23, that is, the metal cathode 23 constituting the red line light emitting element array 6R is selected. The n transparent anodes 21 are connected to a constant current source for a time corresponding to the image data indicating the red density of the first, second, third,..., Nth pixels of the first main scanning line. Thereby, a current having a pulse width corresponding to the image data flows through the organic compound layer 22 (see FIG. 1) between the transparent anode 21 and the metal cathode 23, and red light is emitted from the organic compound layer 22.

  Thus, the exposure light 2 which is red light emitted from the red line-shaped light emitting element array 6R is condensed on the color photosensitive material 3 by the lens array 7, and thereby the first main scanning line is formed on the color photosensitive material 3. The first, second, third,..., N-th pixel constituting the pixel is exposed with red light.

  Next, within the period when the second metal cathode 23, that is, the metal cathode 23 constituting the green line-shaped light emitting element array 6G is selected, the anode driver of the drive circuit 30 is the first, second, third,. Are connected to a constant current source for a time corresponding to image data indicating the green density of the first, second, third,..., Nth pixels of the first main scanning line. As a result, a current having a pulse width corresponding to the image data flows through the organic compound layer 22 between the transparent anode 21 and the metal cathode 23, and green light is emitted from the organic compound layer 22.

  Thus, the exposure light 2 which is green light emitted from the green line-shaped light emitting element array 6G is condensed on the color photosensitive material 3 by the lens array 7, and thereby the first main scanning line is formed on the color photosensitive material 3. The first, second, third,..., N-th pixel constituting the pixel is exposed with green light. Since the color photosensitive material 3 is conveyed at a constant speed as described above, the green light is irradiated onto a portion of the color photosensitive material 3 that has already been exposed to red light.

  Next, within the period when the third metal cathode 23, that is, the metal cathode 23 constituting the blue line-shaped light emitting element array 6B is selected, the anode driver of the drive circuit 30 is the first, second, third. The transparent anodes 21 are connected to a constant current source for a time corresponding to image data indicating the blue density of the first, second, third,..., Nth pixels of the first main scanning line. As a result, a current having a pulse width corresponding to the image data flows through the organic compound layer 22 between the transparent anode 21 and the metal cathode 23, and blue light is emitted from the organic compound layer 22.

  Thus, the exposure light 2 which is blue light emitted from the blue line-shaped light emitting element array 6B is condensed on the color photosensitive material 3 by the lens array 7, and thereby the first main scanning line is formed on the color photosensitive material 3. The first, second, third,..., N-th pixels that are configured are exposed with blue light. Since the color photosensitive material 3 is conveyed at a constant speed as described above, the blue light is irradiated onto the portion of the color photosensitive material 3 that has already been exposed to red light and green light. Through the above steps, the first full-color main scanning line is exposed and recorded on the color photosensitive material 3.

  Next, the line sequential selection of the metal cathodes returns to the first metal cathode 23, and within the period when the first metal cathode 23, that is, the metal cathode 23 constituting the red line light emitting element array 6R is selected. The anode driver of the drive circuit 30 displays the red density of the first, second, third... N transparent pixels 21 and the red density of the first, second, third. Connect to a constant current source for a time corresponding to. As a result, a current having a pulse width corresponding to the image data flows through the organic compound layer 22 between the transparent anode 21 and the metal cathode 23, and red light is emitted from the organic compound layer 22.

  Thus, the exposure light 2 which is red light emitted from the red line-shaped light emitting element array 6R is condensed on the color photosensitive material 3 by the lens array 7, and thereby the second main scanning line is formed on the color photosensitive material 3. The first, second, third,..., N-th pixel constituting the pixel is exposed with red light.

  In the following, the same operation is repeated to expose the second full-color main scanning line. Further, such color main scanning lines are successively exposed in the sub-scanning direction Y, and a large number of color main scanning lines 3 are exposed on the color photosensitive material 3. A two-dimensional color image consisting of main scanning lines is exposed. In the present embodiment, as described above, each color exposure light is subjected to pulse width modulation, and the amount of emitted light is controlled corresponding to the image data, whereby a color gradation image is exposed.

  Next, the optical filter 9 will be described in detail. As described above, the emission spectrum of the organic EL light-emitting elements 20 constituting the line-shaped light-emitting element arrays 6R, 6G, and 6B is broad, and the ends of the respective emission wavelength regions overlap each other. The red photosensitive layer, the green photosensitive layer, and the blue photosensitive layer of the color photosensitive material 3 each have a spectral sensitivity range corresponding to each of the emission wavelength regions, but the spectral characteristics of one photosensitive layer (for example, a blue photosensitive layer). In this state, the end of the emission spectrum (green light emission spectrum) corresponding to the spectral sensitivity range (the spectral sensitivity range of the green photosensitive layer) adjacent to the spectral sensitivity range overlaps the end of the sensitivity range. Therefore, when the color light-sensitive material 3 is directly irradiated with the red light, the green light, and the blue light emitted from the line-shaped light emitting element arrays 6R, 6G, and 6B, the color mixture described in detail above may occur.

Therefore, an optical filter 9 is provided on the organic EL panel 6 in order to prevent this color mixture. The optical filter 9 is formed by forming a dielectric multilayer film that performs a filter function on the surface of a thin transparent substrate such as glass (the surface on the transparent substrate 10 side). As shown in FIG. 3, the optical filter 9 is formed in such a size that the exposure light 2 emitted from all the organic EL light emitting elements 20 of the line light emitting element arrays 6R, 6G and 6B can pass through. Has been. The dielectric multilayer film has, for example, an alternately laminated structure of TiO ₂ / SiO _{2 and} is composed of a total of 20 to 30 layers.

  The transmission spectrum of the optical filter 9 is indicated by a curve F in FIG. In addition, in FIG. 4, the emission spectra of the line-shaped light emitting element arrays 6R, 6G and 6B are shown by curves RE, GE and BE, and the red, green and blue photosensitive layers of the color photosensitive material 3 are shown. Spectral sensitivity characteristics are shown by curves RL, GL and BL.

  That is, the optical filter 9 has a part of a wavelength region (600 nm) where the spectral sensitivity range of the red photosensitive layer and the emission spectrum of green light overlap and the spectral sensitivity range of the green photosensitive layer and the emission spectrum of red light overlap. A first attenuation wavelength region in the vicinity), the spectral sensitivity region of the green photosensitive layer and the emission spectrum of blue light overlap, and the spectral sensitivity region of the blue photosensitive layer and the emission spectrum of green light overlap. A part of the wavelength region (near 500 nm) has the second attenuation wavelength region. The meaning of the term “attenuation” is as described in detail above.

  By providing such an optical filter 9, light emitted from the red line-shaped light emitting element array 6R and capable of exposing the green photosensitive layer, light emitted from the green line-shaped light emitting element array 6G and emitted from the red photosensitive layer or blue. The light that can sensitize the photosensitive layer and the light that can be emitted from the blue line-shaped light emitting element array 6B and that can sensitize the green photosensitive layer are largely cut, so that color mixing in the color photosensitive material 3 is prevented. .

Hereinafter, the effect of preventing the color mixture will be described more specifically. Here, X and Y are set to one of R (red), G (green), and B (blue), respectively, and X-color light is Y-sensitive to energy that sensitizes the X-sensitive layer to be originally exposed by X-color light. The ratio of the energy for exposing the layer is defined as the exposure energy ratio Γ (X → Y). That is, XE is the emission spectrum of X-color light (a function with respect to the wavelength λ of emission intensity), XL and YL are the spectral sensitivity characteristics (functions with respect to the wavelength λ of sensitivity) of the X photosensitive layer and Y photosensitive layer, respectively, Where λ is the wavelength
Γ (X → Y) = ∫XE · YLdλ / ∫XE · XLdλ
It is. Therefore, Γ (X → X) = 1. Further, when the optical filter 9 as described above is used, the transmission spectrum (a function of the transmittance with respect to the wavelength λ) of the filter is F, and the above equation is expressed as Γ (X → Y) = ∫XE · YL · Fdλ / ∫XE / XL / Fdλ
You can use it with a modification.

  As described above, when the exposure energy ratio corrected in the case of using an optical filter is denoted as Γ ′ (X → Y), if Γ ′ (X → Y) <Γ (X → Y), color mixing by the optical filter is performed. The effect of preventing the occurrence is obtained.

Considering such an exposure energy ratio Γ (X → Y), the exposure energy ratio Γ for each combination of each color light and each photosensitive layer is ideally as shown in Table 1 below. In Table 1, X and Y are specifically indicated by R (red), G (green), and B (blue). For example, the numerical values shown in the BE row and the GL column indicate blue light and green light sensitivity. The exposure energy ratio between layers is shown.

When the exposure energy ratio in the exposure apparatus of this embodiment was actually measured, it was as shown in Table 2 below.

On the other hand, when the exposure energy ratio was measured in an exposure apparatus having the same configuration as that of the present embodiment except that the organic EL panel 6 was omitted, it was as shown in Table 3 below.

  Comparing Table 2 and Table 3 above, it is clear that a remarkable color mixing prevention effect is obtained by the present invention.

  FIG. 5 explains the mechanism of color mixing in a negative color photosensitive material in an easy-to-understand manner. Here, as an example, a case where a negative color photosensitive material is exposed with B-color light is considered, and a curve BL (Y) shows the exposure energy versus exposure density characteristic of a photosensitive layer that develops yellow when exposed to B-color light. GL (M) and RL (C) are the same as other magenta photosensitive layers (originally sensitive to G light) and cyan photosensitive colors (originally sensitive to R light). The characteristics are shown. However, the emission spectrum of the B-color light-emitting element has a tail, and the exposure energy ratios Γ (B → G) and Γ (B → R) are respectively G-sensitive to the energy for exposing the B-sensitive layer as described above. The ratio of the energy for exposing the layer, and the ratio of the energy for exposing the R photosensitive layer to the energy for exposing the B photosensitive layer.

  In this case, if the exposure energy ratio Γ (B → G) or Γ (B → R) is larger than the dynamic range A of the photosensitive material, a problem of color mixing occurs. That is, for example, when the dynamic range is 1.5 digits (A = 1.5), no color mixing occurs if the exposure energy ratio Γ (B → G) or Γ (B → R) is 0.03 or less. .

  Further, the optical filter 9 having the above-described effects is not fractionated in units of one pixel as in the color filter described above, but is provided in common for each color of light, and is a complicated photolithography process. Thus, the organic EL panel 6 has a simple configuration and can be easily manufactured at low cost. As a result, the exposure apparatus of the present embodiment using the organic EL panel 6 can also be manufactured at a low cost.

  The optical filter provided in the present invention is not only in the form of the optical filter 9 described above, but also in a state where it is separated from the transparent anode 21 directly under the transparent anode 21, the lower surface of the transparent substrate 10, and the transparent substrate 10. It can also be formed between the array 7, between the lens array 7 and the color photosensitive material 3, on the light passage end face of the lens array 7, and the like.

When the dielectric multilayer film of the optical filter is formed using an inorganic material, the color filter described above is formed even if the filter is formed immediately below the transparent anode 21 made of ITO as described above. As described above, it is possible to prevent the element characteristics and the element life from being adversely affected by the dye diffusion. However, the optical filter used in the present invention is not limited to an inorganic material, and can be formed using an organic material such as a polymer multilayer film. In addition, when an inorganic material is used, the material is not limited to the above-described TiO ₂ or SiO ₂ , and other known multilayer film materials such as Ta ₂ O ₅ and HfO ₂ may be appropriately selected and used. Is possible.

  The attenuation wavelength region of the optical filter 9 partially overlaps the region where the end portions of the emission spectra of the red photosensitive layer, the green photosensitive layer, and the blue photosensitive layer are overlapped. When a large number of element arrays 6R, green line light emitting element arrays 6G, and blue line light emitting element arrays 6B are provided and a color image display device is configured from such an organic EL panel, the optical filter 9 is provided. As described above, the effect of increasing the color purity can be obtained.

  The embodiment applied to the organic EL panel that emits light of three colors of red light, green light, and blue light has been described above. However, the present invention may be applied to an organic EL panel that emits light of other colors. In this case, the same effect can be obtained. In the case of an organic EL panel that emits light of three colors as described above, there are two wavelength regions where color mixing can occur, and in the above embodiment, the optical filter 9 having two attenuation wavelength regions is used correspondingly. However, it is also possible to use an optical filter having one attenuation wavelength region corresponding to only one of the two wavelength regions where color mixing can occur.

  Moreover, although the said embodiment applies this invention to an organic electroluminescent panel, this invention is applicable also to light emitting element arrays, such as a plasma display apparatus and a light emitting diode array, for example. In the above-described embodiment, the three-color independent light emitting type is used as the organic EL panel, but other color filter type or color conversion type organic EL panels may be used in the present invention.

  The present invention is not limited to self-luminous light emitting elements such as organic EL light emitting elements, but can also be applied to color light emitting element arrays using elements composed of a combination of light control elements such as liquid crystal and PLZT and light sources. In this case, the same effect can be obtained.

  Further, the exposure apparatus of the above embodiment is for exposing the image to the color photosensitive material 3 which is a full-color negative type silver salt photographic photosensitive material, but the exposure apparatus of the present invention is for exposing the image to other color photosensitive materials. It is also possible to form as.

1 is a partially cutaway front view of an exposure apparatus according to an embodiment of the present invention. Partially broken side view of the above exposure apparatus Plan view showing a part of the exposure apparatus The graph which shows the emission spectrum of the organic electroluminescent light emitting element used for the said exposure apparatus, the spectral sensitivity characteristic of a color photosensitive material, and the transmission characteristic of an optical filter A diagram for explaining the occurrence of color mixing in a color photosensitive material

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exposure head 2 Exposure light 3 Color photosensitive material 4 Subscanning means 6 Organic electroluminescent panel 6R Red line light emitting element array 6G Green line light emitting element array 6B Blue line light emitting element array 9 Optical filter
20 Organic EL light emitting device
21 Transparent anode
22 Organic compound layer
23 Metal cathode
30 Drive circuit
31 Control unit

Claims (7)

In a color light-emitting element array in which a plurality of types of light-emitting elements each having an emission spectrum that is in a different wavelength region and the ends of the wavelength regions overlap each other are arranged in parallel,
A color light emitting device array, wherein an optical filter having an attenuation wavelength region in at least a part of the overlapping wavelength region is inserted in the optical path of light emitted from the plurality of types of light emitting devices. .   2. The color light emitting element array according to claim 1, wherein only one optical filter is provided in common for the total number of light emitting elements.   3. The color light-emitting element array according to claim 1, wherein the optical filter is made of a dielectric multilayer film.   The color light emitting element array according to any one of claims 1 to 3, wherein the plurality of types of light emitting elements are organic EL light emitting elements.   5. The color light emitting element array according to claim 4, wherein the plurality of kinds of organic EL light emitting elements are three kinds of organic EL light emitting elements that emit light in the wavelength regions of red, green, and blue, respectively. A color light-emitting element array in which a plurality of types of light-emitting elements each having an emission spectrum in a different wavelength region are arranged in parallel;
Means for driving the color light emitting element array based on image data;
A plurality of color photosensitive layers each having spectral sensitivity corresponding to each of the plurality of emission spectra, and corresponding to a spectral sensitivity range adjacent to the spectral sensitivity range at an end of the spectral sensitivity range of one color photosensitive layer; Means for holding a color light-sensitive material having overlapping edges of the emission spectrum;
In an exposure apparatus comprising an imaging lens for forming an image by light emitted from the color light emitting element array on the color photosensitive material,
An optical filter having an attenuation wavelength region in at least a part of the wavelength region where the end of the spectral sensitivity region and the end of the emission spectrum overlap is common to the optical path of the light emitted from the plurality of types of light emitting elements. An exposure apparatus which is inserted into the exposure apparatus. When the color photosensitive material has an X photosensitive layer that is originally exposed with X-color light and a Y photosensitive layer that is originally exposed with Y-color light different from X-color light,
When the optical filter is used when the ratio of the energy of the X color light to sensitize the Y photosensitive layer to the energy of the X color light to sensitize the Y photosensitive layer when the optical filter is not used is Γ (X → Y). Γ ′ (X → Y) <Γ (X → Y) where Γ ′ (X → Y) is the ratio of the energy of X color light to sensitize the X photosensitive layer to the energy of X color light to sensitize the Y photosensitive layer. The exposure apparatus according to claim 6, wherein the relationship is satisfied.

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