JP4561608B2 - Scanning head and dot irradiation element - Google Patents

Description

  The present invention relates to a scanning head having a structure suitable for a printer, a scanner, another image output apparatus or an image dormitory apparatus, and a dot irradiation element of the scanning head.

  Since page printers can also print on plain paper, in recent years, page printers have been actively developed. A conventional page printer uses a laser scanning head in which a laser diode and a polygon lens are combined. However, the laser-type scanning head has a problem that it is difficult to increase the speed and control of printing because the laser light irradiation point is moved by a polygon lens.

  On the other hand, in order to increase the printing speed, an LED type scanning head using a plurality of LEDs has been developed. The LED-type scanning head is mounted such that a plurality of LEDs are arranged in a line, and the photosensitive member is scanned by simultaneously emitting these LEDs with different intensities. However, along with a demand for higher image quality, very high accuracy is required for a high-density mounting technique for a plurality of LEDs, and an increase in the number of components has become a problem.

In order to solve such a problem, a scanning head using an organic electroluminescence element has been proposed (for example, see Patent Document 1).
JP-A-9-226172

  However, even in an organic electroluminescence element, the amount of light that the photoreceptor is sufficiently exposed to is the product of the emission intensity and the exposure time to the photoreceptor, and therefore the emission intensity of the organic electroluminescence element per dot is weak. In addition, the exposure time per dot must be increased. In order to increase the exposure time, the printing speed must be reduced. On the other hand, if the emission intensity per dot of the organic electroluminescence element is increased, the exposure time per dot is shortened and the printing speed is increased, but the life of the organic electroluminescence element is reduced.

  The present invention has been made in view of the above circumstances, and includes a scanning head and a dot irradiation element capable of increasing the amount of light emitted from the light emission surface of the light incident from the light emitting unit without reducing the element lifetime. It is intended to provide.

In order to solve the above problems, the invention of claim 1
A surface light emitting unit array panel in which a plurality of surface light emitting units emitting light in a planar manner are arranged in a line;
A plurality of light guide portions respectively facing the surface light emitting portion,
The light guide part is inclined with respect to the incident surface facing the surface emitting part, a first opposing reflective surface facing the incident surface in a state inclined with respect to the incident surface, and the incident surface, possess a tilt angle formed between the incident face said incident surface and said first opposing reflecting surfaces and not greater than the angle of inclination is the second opposing reflecting surfaces, and an exit surface for emitting light from the surface-emitting portion ,
The light guide portion is connected to the first reflection portion at a boundary surface where the inner surface is a light reflective first reflection portion and the light emitting end surface of the first reflection portion, and the inner surface is a second light reflection property. Surrounded by the reflective part,
The first opposing reflective surface faces the first reflective portion, the second opposing reflective surface faces the second reflective portion,
The second reflecting portion is characterized in that the exit surface facing the boundary surface is opened .

The invention of claim 10
A surface light emitting portion that emits light in a planar manner;
A light guide portion facing the surface light emitting portion;
The light guide unit is inclined with respect to the incident surface facing the surface light emitting unit, a first opposing reflecting surface facing the incident surface in a state inclined with respect to the incident surface, and the incident surface, possess a tilt angle formed between the incident face said incident surface and said first opposing reflecting surfaces and not greater than the angle of inclination is the second opposing reflecting surfaces, and an exit surface for emitting light from the surface-emitting portion ,
The light guide portion is connected to the first reflection portion at a boundary surface where the inner surface is a light reflective first reflection portion and the light emitting end surface of the first reflection portion, and the inner surface is a light reflective second surface. Surrounded by the reflective part,
The first opposing reflective surface faces the first reflective portion, the second opposing reflective surface faces the second reflective portion,
The second reflecting portion is characterized in that the exit surface facing the boundary surface is opened .

  According to the first and tenth aspects of the present invention, the light emitted from the surface light emitting unit is incident on the incident surface of the light guide unit, and the incident light is reflected by the first counter reflecting surface and the second counter reflecting surface. The reflected light is emitted from the emission surface. By propagating through the light guide portion in this way, the second opposing reflecting surface is provided in an inclined state so as to have a narrower angle than the narrow angle between the first opposing reflecting surface and the incident surface. Therefore, the directivity of light in the direction perpendicular to the emission surface can be enhanced.

The invention of claim 2 is the scanning head according to claim 1,
A reflection film is formed on the first counter reflection surface and the second counter reflection surface of the light guide section.

The invention of claim 3 is the scanning head according to claim 1 or 2,
The light guide portion has a first side reflective surface, the peripheral edge of said first side reflecting surface is in contact respectively with the peripheral edge of the peripheral edge and the first opposing reflecting surfaces of the incident surface, high in the first-side reflecting surface This is characterized in that it gradually expands as it approaches the exit surface.

The invention of claim 4 is the scan head according to any one of claims 1 to 3,
The width of the first counter reflecting surface gradually increases as the width approaches the exit surface.

The invention of claim 5 is the scanning head according to any one of claims 1 to 4,
The width of the second opposing reflecting surface gradually increases as it approaches the exit surface.

A sixth aspect of the present invention is the scanning head according to any one of the first to fifth aspects,
The light guide part has a second side reflection surface, the periphery of the second side reflection surface is in contact with the periphery of the second opposing reflection surface , and the height of the second side reflection surface approaches the emission surface. It is characterized by gradually spreading according to.

The invention of claim 7 is the scanning head according to any one of claims 1 to 6,
The surface light emitting unit is an organic electroluminescence element in which a lower electrode, an organic EL layer, and an upper electrode are laminated in this order on a substrate, and the incident surface of the light guide unit faces the upper electrode on the upper electrode side. It is characterized by being.

The invention of claim 8 is the scan head according to any one of claims 1 to 7,
A reflection film is provided on a portion of the incident surface side facing the second opposite reflection surface.

The invention of claim 9 is the scanning head according to any one of claims 1 to 8,
The incident surface overlaps the light emission shape of the surface light emitting unit.

  According to the present invention, it is possible to increase the amount of light emitted from the exit surface of the light incident from the light emitting unit.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, although various technically preferable limitations for implementing the present invention are given to the embodiments described below, the scope of the invention is not limited to the following embodiments and illustrated examples.

  FIG. 1 is a perspective view showing the image output apparatus 1. As shown in FIG. 1, in this image output apparatus 1, a scanning head 2 having a plurality of light emitting elements is arranged such that a light emitting portion thereof faces a bus bar of a photosensitive drum 3 and a longitudinal direction thereof is a roller-like photosensitive member. The drum 3 is arranged so as to be parallel to the rotation axis. Then, between the light emitting portion of the scanning head 2 and the bus of the photosensitive drum 3, the Selfoc lens array 4 includes a plurality of Selfoc lenses having an optical axis on the radial line of the photosensitive drum 3. They are arranged in one or a plurality of rows along the emission part. Light from the light emitting portion of the scanning head 2 is imaged on the generatrix of the photosensitive drum 3 by the Selfoc lens array 4.

  FIG. 2 is a perspective view showing the configuration of 3 dots of light emitting elements in the scanning head 2. The scanning head 2 includes a surface light emitting unit array panel 20 and a plurality of light guide units 60 arranged in a line on the light emitting surface 21 of the surface light emitting unit array panel 20.

FIG. 3 is a plan view of the light emitting surface 21 of the surface light emitting unit array panel 20, and FIG. 4 is a cross-sectional view taken along the thickness direction of the insulating substrate 30 through the cutting line IV-IV in FIG. FIG. 5 is a diagram of FIG.
It is arrow sectional drawing of the surface along the thickness direction of the insulating board | substrate 30 which passes along the cutting line VV of FIG.
As shown in FIGS. 3 to 5, the surface light emitting unit array panel 20 is arranged in a row so as to be positioned on the lower surface of the light guide unit 60 on the insulating substrate 30 and the insulating substrate 30, and viewed in plan view. And a plurality of surface light emitting portions 22 that emit light in a substantially rectangular shape (substantially quadrilateral).

  The surface light emitting unit 22 includes an organic electroluminescence element 27. That is, the surface light emitting unit 22 includes a light-reflective lower electrode 23 formed on the insulating substrate 30, an organic EL layer laminated on the lower electrode 23, and a transparent upper electrode 26.

  For example, as shown in FIG. 4, the organic EL layer includes a hole transport layer 24 and a light emitting layer 25. The hole transport layer 24 includes, for example, PEDOT (polythiophene) that is a conductive polymer and PSS (polystyrene sulfonic acid) that is a dopant. The light emitting layer 25 includes, for example, a conjugated double bond polymer such as polyphenylene vinylene. If the surface light emitting portion 22 emits light as an organic electroluminescence element, the organic EL layer between the lower electrode 23 and the upper electrode 26 does not have a two-layer structure of the hole transport layer 24 and the light emitting layer 25. May be. For example, the layer between the lower electrode 23 and the upper electrode 26 may have a three-layer structure including a hole transport layer, a light emitting layer, and an electron transport layer in order from the lower electrode 23, or a single layer structure including a light emitting layer. It may be a light emitting layer and an electron transport layer, or a layered structure in which an electron or hole transport layer is interposed between appropriate layers in these layer structures. A laminated structure may be used. When the lower electrode 23 is a cathode and the upper electrode 26 is an anode, the lower electrode 23 has an electron transporting charge transport layer, and a hole transporting charge transporting layer is disposed on the upper electrode 26 side.

The lower electrode 23 is preferably reflective to the light of the organic EL layer. When applied as an anode, the lower electrode 23 is made of a material that easily transports holes to the hole transport layer 24. For example, aluminum, It preferably contains a metal such as chromium or titanium. Further, such a reflective conductor layer is provided in the lower layer, and the tin-doped indium oxide (ITO), zinc-doped indium oxide, indium oxide (In ₂ O ₃ ), oxidized so as to be in contact with the hole transport layer 24 in the upper layer. tin (SnO _2), zinc oxide (ZnO), and cadmium - tin oxide or a laminated body in which is arranged a transparent conductive layer containing at least one (CdSnO _4).

The upper electrode 26 is transparent to the light of the organic EL layer and, when applied as a cathode, is provided on the surface in contact with the electron transporting charge transport layer, for example, indium, magnesium, calcium, lithium, barium. A material having a work function lower than that of an anode formed of a single element or an alloy containing at least one rare earth metal and having a thickness of 1 to 20 nm, preferably about 5 to 12 nm, and a sheet resistance as a cathode. And a transparent conductor layer for lowering. The transparent conductor layer is composed of tin-doped indium oxide (ITO), zinc-doped indium oxide, indium oxide (In ₂ O ₃ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), and cadmium-tin oxide (CdSnO _4). ) And a transparent conductor layer containing at least one kind, and when applied as an anode electrode, tin-doped indium oxide (ITO), zinc-doped indium oxide on the surface in contact with the hole-transporting charge transport layer , indium oxide (in ₂ O _3), tin oxide (SnO _2), zinc oxide (ZnO), and cadmium - containing at least one tin oxide (CdSnO _4), the thickness of 30~200nm is preferred.

  In these surface light emitting portions 22, at least one of the upper electrode 26 and the lower electrode 23 is electrically insulated for each organic electroluminescence element 27 so that each organic electroluminescence element 27 emits light appropriately independently. Are formed separately. In the present embodiment, the lower electrode 23 is formed separately for each surface light emitting unit 22, and the upper electrode 26 is formed on the entire surface common to all the surface light emitting units 22.

  The hole transport layer 24 may be formed separately for each surface light emitting unit 22, or may be formed on one surface common to all the surface light emitting units 22. The light emitting layer 25 may also be formed separately for each surface light emitting unit 22, or may be formed on one surface common to all the surface light emitting units 22. In addition, the hole transport layer 24 may be formed on one surface common to all the surface light emitting portions 22, and the light emitting layer 25 may be separately formed as a light emitting layer that emits light of a different color for each surface light emitting portion 22. good. In the present embodiment, both the hole transport layer 24 and the light emitting layer 25 are formed separately for each surface light emitting portion 22.

  In the present embodiment, the lower electrode 23, the hole transport layer 24, and the light emitting layer 25 are formed separately for each surface emitting portion 22, but the lower electrode 23, the hole transport layer 24, and the light emitting layer 25 are formed of the insulating film 28. Therefore, the lower electrode 23, the hole transport layer 24, and the light emitting layer 25 are surrounded by the insulating film 28 in plan view. The insulating film 28 is made of an inorganic material such as silicon nitride or silicon oxide, or a photosensitive resin such as polyimide. Further, although the surface light emitting unit 22 emits light in the light emitting layer 25, the insulating film 28 prevents the light emitted from the light emitting layer 25 of a certain surface light emitting unit 22 from propagating to the light emitting layer 25 of the adjacent surface light emitting unit 22. It is more preferable that the surface of this has light-shielding property.

  The insulating film 28 and the upper electrode 26 are covered with a transparent sealing film 29 having a smooth surface, and the lower electrode 23, the hole transport layer 24, the light emitting layer 25, and the insulating film 28 are sealed with the sealing film 29. Yes. Since the surface light emitting portion 22 is a top emission type organic electroluminescence element, the surface of the sealing film 29 becomes the emission surface of the surface light emitting portion 22.

One light guide unit 60 is opposed to one surface light emitting unit 22, and one surface light emitting unit 22 and one light guide unit 60 facing the surface light emitting unit 22 constitute a dot irradiation element.
Hereinafter, the light guide 60 will be described. As shown in FIGS. 1 to 5, the light guide unit 60 is a cylindrical light reflecting unit in which an incident surface 63 on which light from the surface light emitting unit 22 at a position corresponding to the surface light emitting unit 22 is incident is opened. The periphery is surrounded by 140 and the sealing film 29. The light reflecting portion 140 corresponds to the surface light emitting portion 22 and is disposed at a position where the inner surface of the light reflecting portion 160 and the surface light emitting portion 22 do not overlap with the first light reflecting portion 160 in plan view. The boundary surface 61 that is the light emitting end surface is connected to the first reflecting portion 160, the inner surface is disposed below the light reflecting second reflecting portion 150, and the second reflecting portion 150, and the surface is the light reflecting third surface. And a reflection portion 170. The first reflection unit 160 and the second reflection unit 150 are formed by a continuous reflection film 70. The third reflecting portion 170 is formed by the reflecting film 71. Both the reflective film 70 and the reflective film 71 are made of a light-reflective metal or alloy, and it is preferable that the reflectance of the light from the organic electroluminescence element 27 is high. Silver or aluminum is preferable if the main wavelength region of light emission of the organic electroluminescence element 27 is 400 nm or more, and gold is preferable if it is 600 nm or more.
The first reflecting portion 160 has a shape in which the lower incident surface 63 and the boundary surface 61 corresponding to the surface light emitting portion 22 are opened, and the second reflecting portion 150 faces the boundary surface 61 and the boundary surface 61. The emission surface 52 that is the light emission end surface and the lower surface on the surface light emitting unit 22 side are opened, and the emission surface 52 is aligned with the end surface 30 a of the insulating substrate 30. The third reflecting portion 170 has a planar shape disposed on the opened lower surface of the second reflecting portion 150.
Since the first side reflection surfaces 65 and 66 of the first reflection part 160 are triangular, the space surrounded by the first reflection part 160 and the sealing film 29 in the light guide part 60 is a triangular prism. Further, in the second reflecting portion 150 and the third reflecting portion 170, the boundary surface 61 and the exit surface 52 that are opposed to each other and are open are similar quadrilaterals having different sizes. And the space enclosed by the 3rd reflection part 170 becomes a square frustum.

The light guide 60 includes an incident surface 63, an exit surface 52, a first opposing reflective surface 64 on the opposite side of the incident surface 63, and a first portion between the peripheral edge of the incident surface 63 and the peripheral edge of the first opposing reflective surface 64. The first reflecting surfaces 65 and 66, the second reflecting surface 53 on the extended plane of the incident surface 63 (the upper surface of the sealing film 29), and the first opposing reflecting surface 64 are provided in succession. Second opposing reflection surface 54 facing second reflection surface 53 in a state inclined with respect to reflection surface 53, and second side reflection between the peripheral edge of second reflective surface 53 and the peripheral edge of second counter reflective surface 54. And surfaces 55 and 56.
The reflective film 70 in the first reflective portion 160 includes a light-reflective first counter-reflective surface 64 that faces the incident surface 63, and light reflectivity between the periphery of the incident surface 63 and the periphery of the first counter-reflective surface 64. The first side reflection surfaces 65 and 66 are in contact with each other.
The surface of the reflective film 71 of the third reflective portion 170 formed on the sealing film 29 is in contact with the light reflective second reflective surface 53.
The reflective film 70 in the second reflective portion 150 faces the second reflective surface 53 of the third reflective portion 170, is provided continuously along the first opposing reflective surface 64, and is inclined with respect to the second reflective surface 53. The light-reflective second opposing reflecting surface 54 in contact with the second reflecting surfaces 55 and 56 between the periphery of the second reflecting surface 53 and the periphery of the second opposing reflecting surface 54.
The light incident on the light guide unit 60 in the light reflection unit 140 from the surface light emitting unit 22 is reflected in the light reflection unit 140 and emitted from the emission surface 52 or directly emitted from the emission surface 52. Is set to
In addition, the lower electrode 23 is a reflective surface that reflects directly incident light among the light emitted from the light emitting layer 25 or the light reflected by the first counter reflective surface 64 and the first side reflective surfaces 65 and 66. It also has a function as

The incident surface 63 is inclined with respect to the first opposing reflecting surface 64. The boundary surface 61 (surface opposite to the narrow angle between the incident surface 63 and the first opposing reflecting surface 64) 61 between the first reflecting portion 160 and the second reflecting portion 150 and the incident surface 63 are substantially perpendicular to each other. Has been. The first side reflecting surfaces 65 and 66 are both orthogonal to the incident surface 63 and the side in contact with the first opposing reflecting surface 64 has a predetermined elevation angle θ (θ> 0 °) from the end 62 to the boundary surface. Since it has a substantially wedge shape, the cross-sectional area of the surface cut parallel to the boundary surface 61 gradually increases from the end 62 to the boundary surface 61, that is, as it approaches the boundary surface 61.
In addition, the incident surface 63 and the first opposing reflecting surface 64 have substantially the same length in the width direction W of the light guide portion 60 from the end portion 62 to the boundary surface 61. The incident surface 63 and the first opposing reflecting surface 64 have a rectangular shape (a quadrilateral shape) that is long from the end 62 to the boundary surface 61. The area of the incident surface 63 is larger than the area of the boundary surface 61. Specifically, the incident surface 63 is a rectangle of 300 μm × 10 μm, the area is 3000 μm ² , and the boundary surface 61 is a rectangle of 10 μm × 5 μm. The area is 50 μm ² .
Further, the first side reflection surfaces 65 and 66 are gradually increased in length in the height direction H of the light guide portion 60 from the end portion 62 to the boundary surface 61, that is, as the boundary surface 61 is approached.

The exit surface 52 and the second reflecting surface 53 are both inclined with respect to the second opposing reflecting surface 54. The exit surface 52 is a surface facing the end portion 62 having a narrow angle between the first opposing reflection surface 64 and the entrance surface 63. The exit surface 52 has a narrow angle with the second reflecting surface 53 substantially perpendicular.
The second side reflection surfaces 55 and 56 are both orthogonal to the second reflection surface 53 and the side in contact with the second opposing reflection surface 54 extends from the boundary surface to the emission surface 52 at a predetermined elevation angle θ ′ (θ ′> θ)), the cross-sectional area of the surface cut parallel to the emission surface 52 gradually increases from the boundary surface 61 to the emission surface 52, that is, as the emission surface 52 is approached. The area of the incident surface 63 is larger than the area of the exit surface 52. Specifically, the exit surface 52 is a rectangle of 20 μm × 10 μm, and the area is 200 μm ² .
Since the elevation angle θ ′ is larger than the elevation angle θ, the first opposing reflecting surface 64 and the second opposing reflecting surface 54 are formed in a valley shape on the boundary surface 61.
In addition, the second reflecting surface 53 and the second opposing reflecting surface 54 are gradually longer in the width direction W from the boundary surface 61 to the emission surface 52. The second reflection surfaces 55 and 56 have a length in the height H direction that gradually increases from the boundary surface 61 to the emission surface 52.

  The reflective film 70 is preferably formed continuously with the first reflective portion 160 and the second reflective portion 150, but may have a structure separated by the boundary surface 61. The shape of the first opposing reflecting surface 64 and the shape of the reflecting film 70 at the first reflecting portion 160 in contact with the first opposing reflecting surface 64 are substantially rectangular in plan view as shown in FIG. As shown in FIG. 4, the shape of the first reflective surfaces 65 and 66 and the shape of the reflective film 70 at the first reflective portion 160 in contact with the first reflective surfaces 65 and 66 are triangular. The shape of the second opposing reflecting surface 54 and the shape of the reflecting film 70 at the second reflecting portion 150 in contact with the second opposing reflecting surface 54 are trapezoidal as shown in FIG. As shown in FIG. 4, the shape of the reflection film 70 at the second reflection portion 150 in contact with the shape of 55, 56 and the second side reflection surfaces 55, 56 is trapezoidal. The shape of the second reflective surface 53 and the shape of the reflective film 71 at the third reflective portion 170 in contact with the second reflective surface 53 are trapezoidal.

  As shown in FIG. 3, the surface light emitting unit 22 has a similar shape with substantially the same size as the incident surface 63, and emits surface light in a rectangular shape extending from one end 31 to the other end 32. The area of the surface light emitting unit 22 is 80% to 110%, preferably 85% to 99% of the area of the incident surface 63 of the light guide unit 60. In order for the surface light emitting portion 22 to emit light in a rectangular shape, the upper electrode 26 and the lower electrode 23 are electrically formed independently for each surface light emitting portion 22. In this embodiment, the lower electrode 23 is rectangular. It is formed in a shape. Each surface light emitting unit 22 preferably overlaps only the corresponding incident surface 63 so that light is not emitted to the light guide unit 60 corresponding to the adjacent surface light emitting unit 22.

  Then, the incident surface 63 comes into contact with the emission surface of the surface light emitting portion 22, the incident surface 63 overlaps the light emission shape of the surface light emitting portion 22, and the end portion 62 is near the edge of the one end 31 of the surface light emitting portion 22. The boundary surface 61 is parallel to the base of the other end 32 of the surface light emitting unit 22. As shown in FIG. 3, the main axis direction from one end 31 to the other end 32 of the surface light emitting unit 22 coincides with the direction of the main axis Ax of the light guide unit 60 as viewed from the normal direction of the surface light emitting unit 22.

  The reflective film 70 of the light reflecting section 140 that defines the shape of the light guide section 60 is a reflective material that becomes the reflective film 70 in a three-dimensional mold whose depth is controlled by changing the acceleration voltage during electron beam exposure. Can be three-dimensionally molded by injecting.

  As shown in FIG. 1, the emission surfaces 52 of the plurality of light guides 60 serve as the light emission parts of the scanning head 2, and the light is emitted so that the principal axis Ax of the light guides 60 coincides with the optical axis of the SELFOC lens array 4. The surface 52 faces the incident surface of the SELFOC lens array 4.

  A driving circuit 80 is provided on one surface of the surface light emitting unit array panel 20, and the wiring 33 of each surface light emitting unit 22 is connected to the driving circuit 80. The driving circuit 80 performs wiring based on an image signal serving as print data. A desired voltage or current is applied to each organic electroluminescence element 27 through 33 so that the organic electroluminescence element 27 emits light appropriately.

  At this time, since the shape of the light emitting layer 25 that overlaps the lower electrode 23 and the upper electrode 26 is rectangular, the surface light emitting portion 22 emits light in a rectangular shape. Then, the light emitted from the surface light emitting unit 22 enters the incident surface 63 of the light guide unit 60. The incident light is repeatedly reflected on the incident surface 63, the first opposing reflecting surface 64, and the first side reflecting surfaces 65 and 66 by the elevation angle θ and propagates in the first reflecting portion 160, and further, the incident light is transmitted by the elevation angle θ ′. While repeating the reflection on the second reflecting surface 53, the second opposing reflecting surface 54, and the second side reflecting surfaces 55, 56, the light guide unit is given directivity that proceeds toward the exit surface 52 side. The light propagates through the light guide 60 and exits from the light exit surface 52 of the light guide 60 along the main axis Ax of the light guide 60. In this way, the light guide 60 itself functions as a light adjustment unit that adjusts the directivity of incident light. Therefore, the light incident on the incident surface 63 of the light guide unit 60 is efficiently emitted from the emission surface 52 from the emission surface 52, and the directivity of light in the direction perpendicular to the emission surface 52 is increased. Then, the light emitted from the emission surface 52 is imaged on the generatrix of the photosensitive drum 3 rotated by the Selfoc lens array 4, and an image is formed on the side surface of the photosensitive drum 3.

Next, as shown in FIG. 6, the side surface defined by only the first reflection unit 160 described above is a triangular prism-shaped light guide unit (comparative example), the first reflection unit 160, the second reflection unit 150, and the first reflection unit 160. In the light guide part 60 (example of the present invention) defined by the three reflection parts 170, the amount of light emitted from the emission surface was compared. The surface emitting portion 22 is set to the same shape and the same size in both the comparative example and the present invention example, and the first reflecting portion 160 is also set to the same shape and the same size in both the comparative example and the present invention example. Then, the boundary surface 61, which is the light emitting end surface of the first reflecting portion 160, is flush with the end surface 30 a of the insulating substrate 30.
The light guide section 60 in the first reflecting section 160 is set to have a length of 300 μm, a width of 10 μm, and a height at the boundary surface 61 of 5 μm. The light guide unit 60 in the second reflecting unit 160 and the third reflecting unit 170 has a length of 40 μm, a width of 10 μm at the boundary surface 61, a width of 20 μm at the output surface 52, a height of 5 μm at the boundary surface 61, and an output surface 52. The height at 10 is set to 10 μm.
It is assumed that the first reflecting portion 160 and the second reflecting portion 150 are filled with air (refractive index 1.00) and that the luminous flux density per 1 μm ² area of the surface light emitting portion 22 is “1”. Differences in the amount of light emitted within 25 ° with respect to the direction of the principal axis Ax of the optical unit 60 were compared with relative values.
Of the light emitted from the emission surface, the amount of light emitted within 25 ° with respect to the direction of the main axis Ax is “131” in the comparative example, whereas “420” is obtained in the present invention example. I was able to. Therefore, the amount of light emitted within 25 ° can be increased to about 3.2 times the conventional amount.

  As described above, according to the embodiment of the present invention, the light emitted from the surface light emitting unit 22 enters the incident surface 63 of the light guide unit 60, propagates through the light guide unit 60, and emits light from the output surface 52. . The second opposing reflecting surface 54 is provided in a state inclined with respect to the second reflecting surface 53 so as to have a narrow angle θ ′ larger than the narrow angle θ between the first opposing reflecting surface 64 and the incident surface 63. Therefore, the directivity of light in the direction perpendicular to the emission surface 52 can be increased, and the amount of light emitted can be increased without reducing the element lifetime. As a result, crosstalk between adjacent pixels can be prevented.

  Further, since the area of the emission surface 52 is smaller than the area of the incident surface 63, the light incident on the incident surface 63 from the surface light emitting unit 22 is emitted from the emission surface 52 in a converged state. Even if the light emission intensity per unit area of the surface light emitting unit 22 is low, light is emitted with high intensity on the emission surface 52. For this reason, the photosensitive drum 3 is exposed to light in a short exposure time, so that the photosensitive drum 3 can be rotated at a high speed, and thus the printing time can be shortened.

  Further, in order to increase the intensity of light emitted from the emission surface 52, it is conceivable to increase the emission intensity of the surface light emitting unit 22. However, increasing the emission intensity of the surface light emitting unit 22 shortens the life of the surface light emitting unit 22. It leads to things. However, since the light incident on the incident surface 63 from the surface light emitting portion 22 is emitted from the emission surface 52 in a converged state, the light emitted from the emission surface 52 can also be increased by increasing the light emitting area of the surface light emitting portion 22. Strength can be increased. Even if the light emitting area of the surface light emitting portion 22 is increased, if the area of the incident surface 63 is increased accordingly, the light intensity at the output surface 52 is increased without increasing the area of the output surface 52. Therefore, the dot diameter does not increase and a high resolution image can be formed.

  Further, since the shape of the light guide unit 60 is set so that the light incident on the light guide unit 60 easily travels toward the output surface 52, the light taken in from the incident surface 63 can be efficiently emitted. Furthermore, since the directivity that increases the light intensity at the main axis Ax of the light guide unit 60 is given, the light can be efficiently incident on the Selfoc lens array 4 and the light use efficiency is improved, so that the light intensity is short. The photosensitive drum 3 is exposed to light during the exposure time, and the photosensitive drum 3 can be rotated at a high speed, so that the printing time can be shortened.

The present invention is not limited to the above embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.
For example, the light guide section 60 partitioned by the reflective film 70 and the reflective film 71 is filled with a gas such as air having translucency. Materials such as polydimethylsiloxane resin, fluororesin made of a polymer such as ethylene fluoride or propylene fluoride, epoxy thermosetting resin, glass, etc., low refractive index transparent liquid material such as water (refractive index n _D ²⁰ = 1.33), methyl alcohol (refractive index n _D ²⁰ = 1.32), and ethyl alcohol (refractive index n _D ²⁰ = 1.36) may be applied. However, in the case of a liquid material, it is necessary to sufficiently seal with another transparent member so as not to leak from the emission surface 52 and the like. As a method for forming the light guide portion in the case of a solid material, for example, a solution in which the solid material is dissolved may be poured into a resist pattern template that has been finely processed into a nanosize by a nanoimprint technique and solidified. The refractive index is preferably as close to 1 as air, and the resin is preferably 1.5 or less. And what is necessary is just to form a reflective surface by forming a reflecting film in the predetermined location of a light guide part.

Moreover, in the said embodiment, as shown in FIG. 7, the 2nd reflection part 150 does not provide the reflecting film 71, but the surface emitting part 22 on the insulating substrate 30 is made into the lower surface of the 2nd reflection part 150, for example. The light-reflecting lower electrode 23 of the organic electroluminescence element 27 may be used as the third reflecting portion 170.
Moreover, in the said embodiment, the surface light emission part 22 (The light emitting layer 25 of the part which overlaps with the lower electrode 23 and the upper electrode 26), the incident surface 63 of the light guide part 60, the 1st opposing reflective surface 64, and a 1st opposing reflective surface Although the first reflecting portions 160 in contact with 64 are all rectangular, they may be triangular as shown in FIGS. That is, the light emission unit 60 in the first reflection unit 160 may be a quadrangular pyramid with the boundary surface 61 as a bottom surface, so that the emission efficiency may be improved. Even in this case, θ ′> θ. Further, the angle α of the end portion 162 in the first reflecting portion 160 and the angle α ′ corresponding to the second opposing reflecting surface 54 in the second reflecting portion 150 are set to satisfy α <α ′. In such a shape, an insulating film may be formed so as to cover the periphery of the lower electrode 23, and the opening in the insulating film through which the lower electrode 23 is exposed may be triangular. The surface light emitting unit 22 (the light emitting layer 25 that overlaps the lower electrode 23 and the upper electrode 26), the incident surface 63 of the light guide unit 60, the first opposing reflecting surface 64, and the first opposing reflecting surface 64 are in contact with each other. The reflector 160 may be trapezoidal as shown in FIG. Even in this case, θ ′> θ. Further, the angle β of the end portion 262 in the first reflecting portion 160 and the angle β ′ corresponding to the second opposing reflecting surface 54 in the second reflecting portion 150 are set to satisfy β <β ′. In such a shape, an insulating film may be formed so as to cover the periphery of the lower electrode 23, and the opening in the insulating film from which the lower electrode 23 is exposed may be trapezoidal.
Moreover, as long as there is consistency, the configurations of such modifications may be combined as appropriate.

1 is a perspective view of an image output device 1. FIG. 3 is a perspective view showing a configuration for 3 dots in the scanning head 2. FIG. 4 is a plan view of a light emitting surface 21 of a surface emitting unit array panel 20 for 4 dots. FIG. FIG. 4 is a cross-sectional view taken along an arrow line IV-IV in FIG. 3. It is arrow sectional drawing of the surface along the cutting line VV of FIG. It is the perspective view which showed the structure for 3 dots among the scanning heads of a comparative example. FIG. 3 is a cross-sectional view of the scanning head 2 cut in the main axis direction. 3 is a perspective view showing a configuration for 3 dots in the scanning head 2. FIG. 4 is a plan view of a light emitting surface 21 of a surface emitting unit array panel 20 for 4 dots. FIG. 4 is a plan view of a light emitting surface 21 of a surface emitting unit array panel 20 for 4 dots. FIG.

Explanation of symbols

20 surface light emitting unit array panel 22 surface light emitting unit 52 light emitting surface 53 second reflecting surface 54 second counter reflecting surface 55, 56 second side reflecting surface 60 light guide unit 63 incident surface 64 first counter reflecting surface 65, 66 first Side reflection surface

Claims (10)

A surface light emitting unit array panel in which a plurality of surface light emitting units emitting light in a planar manner are arranged in a line;
A plurality of light guide portions respectively facing the surface light emitting portion,
The light guide part is inclined with respect to the incident surface facing the surface emitting part, a first opposing reflective surface facing the incident surface in a state inclined with respect to the incident surface, and the incident surface, possess a tilt angle formed between the incident face said incident surface and said first opposing reflecting surfaces and not greater than the angle of inclination is the second opposing reflecting surfaces, and an exit surface for emitting light from the surface-emitting portion ,
The light guide portion is connected to the first reflection portion at a boundary surface where the inner surface is a light reflective first reflection portion and the light emitting end surface of the first reflection portion, and the inner surface is a second light reflection property. Surrounded by the reflective part,
The first opposing reflective surface faces the first reflective portion, the second opposing reflective surface faces the second reflective portion,
The scanning head, wherein the second reflecting portion has an opening at the exit surface facing the boundary surface .   2. The scanning head according to claim 1, wherein a reflection film is formed on the first counter reflection surface and the second counter reflection surface of the light guide unit. The light guide portion has a first side reflective surface, the peripheral edge of said first side reflecting surface is in contact respectively with the peripheral edge of the peripheral edge and the first opposing reflecting surfaces of the incident surface, high in the first-side reflecting surface 3. The scanning head according to claim 1, wherein the scanning head gradually spreads toward the exit surface. 4.   4. The scanning head according to claim 1, wherein the width of the first opposing reflecting surface gradually increases as the width approaches the exit surface. 5.   5. The scanning head according to claim 1, wherein the width of the second opposing reflection surface gradually increases as the width approaches the exit surface. 6. The light guide part has a second side reflection surface, the periphery of the second side reflection surface is in contact with the periphery of the second opposing reflection surface , and the height of the second side reflection surface approaches the emission surface. 6. The scanning head according to claim 1, wherein the scanning head gradually spreads along with the scanning head.   The surface light emitting unit is an organic electroluminescence element in which a lower electrode, an organic EL layer, and an upper electrode are laminated in this order on a substrate, and the incident surface of the light guide unit faces the upper electrode on the upper electrode side. The scanning head according to claim 1, wherein the scanning head is provided.   8. The scanning head according to claim 1, wherein a reflection film is provided on a portion of the incident surface side surface facing the second counter reflection surface. 9.   The scanning head according to claim 1, wherein the incident surface overlaps a light emission shape of the surface light emitting unit. A surface light emitting portion that emits light in a planar manner;
And a light guiding portion which is opposite to the surface emitting unit,
The light guide part is inclined with respect to the incident surface facing the surface emitting part, a first opposing reflective surface facing the incident surface in a state inclined with respect to the incident surface, and the incident surface, possess a tilt angle formed between the incident face said incident surface and said first opposing reflecting surfaces and not greater than the angle of inclination is the second opposing reflecting surfaces, and an exit surface for emitting light from the surface-emitting portion ,
The light guide portion is connected to the first reflection portion at a boundary surface where the inner surface is a light reflective first reflection portion and the light emitting end surface of the first reflection portion, and the inner surface is a second light reflection property. Surrounded by the reflective part,
The first opposing reflective surface faces the first reflective portion, the second opposing reflective surface faces the second reflective portion,
The dot irradiating element, wherein the second reflecting portion has an opening at the exit surface facing the boundary surface .

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