JP2000106458A - Light emitting device for writing image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting device that is used for writing a picture image, improved in utilization of light emitted from a light emitting element, and capable of enhancing the light emitting element in emission power. SOLUTION: A light emitting device for writing a picture image is equipped with a light emitting element 33 mounted on and connected to a printed wiring board 31, a shield plate 34 arranged confronting the light emitting element 33 in the direction of light emission, and a light transmission structure provided in the shield plate 34 facing the light output plane of the light emitting element 33, where the light transmission structure is formed so large in size as to include all the contour of the light output plane of the light emitting element, and a reflecting means that reflects light leaking out through a part other than a light output plane is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image writing light emitting device used as an image writing device of an optical exposure type printer for writing an image on a self-developing type instant film.

[0002]

2. Description of the Related Art For example, a full-color printer for outputting an image, such as a digital video camera or a personal computer, is provided with a writing device for forming an image. As this writing device, photosensitive R, G, B
R, G, B light-emitting diodes (hereinafter, referred to as “recording paper”) using a recording paper provided with a microcapsule sensitive to any one of
An LED head of an LED lens optical exposure system for writing an image by exposure using “LED” has already been proposed.

The basic configuration of a writing device is to arrange a plate such as a stainless steel plate at a parallel interval with respect to a printed circuit board, and to arrange light emitting elements between the plate and the printed circuit board as a mounting surface. Things. In the past, a configuration in which a spherical lens for easily condensing light from a light emitting element on recording paper was incorporated into a plate corresponding to the light emitting element was mainly used.

However, in the case of using such a lens, in order to increase the irradiance on the recording paper, it is necessary to increase the diameter of the opening in which the lens is incorporated in the plate and to receive a large amount of radiant flux from the light emitting element. . Although this can be dealt with by increasing the diameter of the lens, the optical path length becomes longer and aberrations occur, so that an appropriate beam necessary for recording cannot be obtained, which greatly affects the accuracy of image writing.

On the other hand, the applicant of the present invention has proposed a light-emitting recording apparatus capable of maintaining high use efficiency of light from a light-emitting element, irradiating a recording sheet with a higher irradiance, and shortening a printing time and reducing the size. And proposed Japanese Patent Application No. Hei 10-12
No. 475.

The light-emitting recording apparatus according to the present application includes a plate disposed at a distance from a printed wiring board, and a plurality of light-emitting elements whose light emitting directions are on the plate side are mounted on the printed wiring board. Further, the plate is provided with a light transmitting portion for transmitting light at a position corresponding to the light emitting element. The light transmitting portion is, for example, a circular optical light transmitting window having a diameter of 1 mm or less.

In a writing device incorporating a plate having such a light-transmitting window, only the light emitted from the light-emitting element passes through the light-transmitting window and is applied to the surface of the recording paper, and unnecessary light is blocked by the plate. This makes it possible to write a high-resolution image, and because the lens is not included in the optical path, the optical path is short and the influence of aberration is eliminated, the efficiency of using light from the light emitting element is improved, and radiation to recording paper is improved. Illuminance can also be increased.

[0008]

However, the assembly of the light-emitting element, including that of the earlier application, is larger than the light-transmitting window. This is because, if the light emitting element is made too small, the total radiant flux emitted from the light emitting element decreases, and sufficient light radiation power cannot be obtained.

According to the relationship between the size of the light emitting element and the size of the light transmitting window, the light emitting element has not only the main light extraction surface but also light components that pass to the side, so that the entire light emission is light transmitting. It is blocked by the back of the plate without being irradiated from the window. For this reason, even if a light emitting element having a high radiation power is used, the light quantity taken out of the light transmitting window and irradiated on the recording paper is reduced, and the light use efficiency is reduced.

Further, in order to allow more light from the main light extraction surface of the light emitting element to pass through the light transmitting window, the size of the light emitting element may be made smaller than that of the light transmitting window. However, as described above, as the size of the light emitting element is reduced, the total radiant flux is also reduced, which has a considerable effect on image writing. Therefore, the light emitting element is restricted by a light emitting element having a certain size so that the radiant flux becomes high, which may be an obstacle to cost reduction.

An object of the present invention is to provide a light emitting device capable of improving the use efficiency and radiated power of light emitted from a light emitting element.

[0012]

SUMMARY OF THE INVENTION The present invention provides a wiring board,
A light emitting element conductively mounted on the wiring board, a shield plate disposed to face the light emitting direction of the light emitting element, and a light transmission structure provided on the shield plate facing a light extraction surface of the light emitting element. An image writing light-emitting device comprising: a light-transmitting structure having a shape having a size including an entire outer periphery of a light extraction surface of the light-emitting element; and light leaking from around the light-emitting element except from the light-extraction surface. A reflecting means for reflecting the light in the direction of the light transmitting structure.

[0013]

The invention according to claim 1 includes a wiring board, a light emitting element conductively mounted on the wiring board, a shield plate arranged to face a light emitting direction of the light emitting element, and A light transmission structure provided on the shield plate facing the light extraction surface of the light emitting element, wherein the light transmission structure has a size including an entire outer periphery of the light extraction surface of the light emitting element. A light emitting device for image writing, comprising a reflection means for reflecting light leaking from other than the light extraction surface in the direction of the light transmitting structure around the light emitting element. Almost all of the emitted light can be applied to the recording medium as light passing through the light transmitting structure, and the reflecting means also has the effect of increasing the light use efficiency.

According to a second aspect of the present invention, there is provided a wiring board, a submount element conductively mounted on the wiring board, a light emitting element conductively mounted on the submount element, and facing a light emitting direction of the light emitting element. And a light-transmitting structure provided on the shield plate facing the light extraction surface of the light-emitting element, wherein the light-transmitting structure is a light-emitting element of the light-emitting element. A light emitting device for image writing, which has a shape having a size including the entire outer periphery of the light extraction surface, and wherein the submount element includes a reflection unit that reflects light leaking from a portion other than the light extraction surface toward the light transmission structure. Even if the light emitting element is made small, almost all of the light emission can be emitted to the recording medium as light passing through the light transmission structure, and the submount element can be used only as a function of the element. Ku has the effect that can be utilized as a utilization efficiency enhancing member of the light from the light emitting element.

According to a third aspect of the present invention, there is provided a mounting board having a light transmitting structure formed in a part thereof, a mount block having a concave cross section, and having the concave portion facing one surface side of the wiring board and being conductively fixed; A light-emitting element which is conductively fixed in the concave portion of the mount block and has a light extraction surface facing the light transmission structure, wherein the light transmission structure has a size including an entire outer periphery of the light extraction surface of the light emission element. A light emitting device for writing an image, comprising a reflecting means for reflecting light leaking from a portion other than the light extraction surface toward the light transmitting structure in the concave portion of the mount block. And a mount block for conducting and fixing the light emitting element to improve the utilization efficiency of the light from the light emitting element. It has the effect of being able to take advantage of even.

According to a fourth aspect of the present invention, there is provided the image writing light emitting device according to any one of the first to third aspects, wherein an optical axis of the light emitting element is substantially aligned with a core of the light transmitting structure. It has an effect that the use efficiency of light emitted from the light emitting element is high and the recording medium can be irradiated with higher irradiance.

According to a fifth aspect of the present invention, a light transmitting resin is filled between the light transmitting structure and at least a portion of the light emitting element where the light extraction surface faces the light transmitting structure. 5. The light-emitting device for image writing according to any one of 1 to 4, wherein light from the light-emitting element can be efficiently taken into the light-transmitting structure, and the use efficiency of light from the light-emitting element is high and the recording medium is higher. It has the effect of being able to irradiate with irradiance.

According to a sixth aspect of the present invention, light from the light extraction surface is condensed between the light extraction surface of the light emitting element and the light transmission structure to form an optical path to the light transmission structure. The light emitting device for image writing according to any one of claims 1 to 5, further comprising a spherical lens that converges light from the light emitting element by the spherical lens. It has the effect of irradiating with higher irradiance.

According to a seventh aspect of the present invention, the wiring board includes a metal base, an insulating film laminated on the base, and a wiring pattern formed on a surface of the base. The image writing light emitting device according to any one of claims 1 to 6, further comprising: a fin having a function of preserving a function of the light emitting element by radiating heat by the fin.

According to an eighth aspect of the present invention, the wiring board comprises a metal base mounted and fixed on a fixing member on the device side, an insulating film laminated on the base, and a wiring pattern formed on the surface thereof. The light-emitting device for image writing according to any one of claims 1 to 6, wherein the surface roughness of the base and the fixing member is reduced, and the base member and the fixing member are joined by a heat-dissipating fixed grease. By increasing the heat transfer area by manipulating heat radiation and surface roughness,
This has the function of maintaining the function of the light emitting element.

According to a ninth aspect of the present invention, in the light emitting device for image writing according to any one of the first to eighth aspects, the light transmitting structure is a hole formed in the shield plate.
It has an effect that a light transmitting structure can be easily obtained only by drilling.

According to a tenth aspect of the present invention, there is provided the image writing light emitting device according to the ninth aspect, wherein a light transmitting resin is filled inside the hole of the light transmitting structure. The light-transmitting resin has an effect of preventing entry of dust from the outside and clogging of an optical path.

According to a twelfth aspect of the present invention, there is provided the light emitting device for image writing according to the ninth or tenth aspect, wherein a light transmissive coating layer is formed including the holes of the light transmitting structure. This has the effect of preventing intrusion of dust into the holes and damage to the light transmitting resin filled in the holes.

According to a twelfth aspect of the present invention, in the light emitting device for image writing according to the ninth aspect, a lens for condensing light from the light emitting element is provided in the hole of the light transmitting structure. Has the effect that the light from the recording medium can be more efficiently irradiated onto the recording medium.

Hereinafter, a specific example of the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an embodiment of the invention according to claim 1 of the present invention, and is a longitudinal sectional view showing a main part of a light emitting device.

In FIG. 1, wiring patterns 32a and 32a are formed on the surface of a printed wiring board 31 which is arranged to face recording paper.
The light-emitting element 33 is mounted on the substrate, and a shield plate 34 is disposed above the light-emitting element 33. The printed wiring board 31 and the shield plate 34 are developed in a plane in the left, right, and depth directions of the drawing, and a large number of light emitting elements are arranged in a uniform pattern therebetween as described later.

The light emitting element 33 emits blue light using, for example, a GaN-based compound semiconductor. A GaN n-type layer 33b and a GaN p-type layer 33c are formed on a substrate 33a using sapphire.
Are laminated. Then, the n-type layer 33b and the p-type layer 33c
An n-electrode 33d and a p-electrode 33e are formed on the respective surfaces of
3f and 33g are used to bond to the wiring patterns 32a and 32b. Therefore, the wiring pattern 32
a, 32b, the n-type layer 33b and the p-type layer 3
3c, light is emitted from the active layer, and n and p electrodes 33
With the upper surface on which d and 33e are formed as the main light extraction surface, upward light emission in the figure is obtained.

On the other hand, the shield plate 34 is provided with a light transmitting window 34a as a light transmitting structure in conformity with the arrangement pattern of the light emitting elements 33. That is, when the shield plate 34 is made of, for example, a transparent glass plate, the surface is light-shielded by the mask pattern 34b so that only the light transmission window 34a is an opening through which light can be transmitted, and all portions except the light transmission window 34a are light-shielded. Have been. The light transmission window 34 a has an opening cross section larger than the planar outer shape of the light emitting element 33, and the center thereof is set to be substantially coincident with the optical axis of the light emitting element 33.

The space between the printed wiring board 31 and the shield plate 34 is filled with a light-reflective resin layer 35 so as to surround the light emitting element 33. The resin layer 35 has an upper end side substantially equal to the inner diameter of the light transmission window 34 a and the light emitting element 3.
The inner peripheral surface around 3 is formed in a mortar shape toward the lower end side. By providing the resin layer 35 in this manner, light leaking laterally from the active layer of the light emitting element 33 is reflected by the inner peripheral surface of the resin layer 35, and the light transmission window 34a is formed.
Can be collected on the side.

In the above configuration, when the light-emitting element 33 is energized, the light leaking to the side is collected on the side of the light transmitting window 34a with the inner peripheral surface of the light-reflective resin layer 35 serving as a reflecting surface.
The radiation power is greatly improved in combination with the light from the main light extraction surface. Further, since the light from the light emitting element 33 is irradiated to the recording medium side from the light transmission window 34a which is larger than this, the entire light emission from the main light extraction surface of the light emitting element 33 can be used for image writing.

By making the size of the light emitting element 33 smaller than that of the light transmission window 34a, light emitted from the entire main light extraction surface can be used as light for irradiating the recording medium. Therefore, even when the light other than the light transmitting window 34a is shielded, the light emitted from the light emitting element 33 can be effectively used. Further, even if the light emitting element 33 is made small, the light from the reflection surface of the light-reflective resin layer 35 can be collected, so that the irradiation power does not decrease. For this reason, since there is no problem even if the radiation power of the light emitting element 33 is reduced by an amount corresponding to the light collected from the reflection surface, cost reduction is achieved by downsizing the light emitting element 33.

In the example shown in FIG. 1, the light reflecting resin layer 35 is used as the reflecting means, but instead, a metal plate having a high light reflectance is insulated and short-circuited with the wiring patterns 32a and 32b. It may be arranged around the light emitting element 33 so as not to be reflected.

FIG. 2 is a longitudinal sectional view showing a main part of another example of the light emitting device of the present invention. In FIG. 2, a wiring pattern 2a,
2b, the composite semiconductor light emitting element A is conductively mounted on the wiring pattern 2a, the wiring pattern 2b is bonded to the wiring pattern 2b with the wire 3, and a shield plate 4 is disposed on the composite semiconductor light emitting element A. I have.

The printed wiring board 1 is made of a metal base 1a.
The shield plate 4 is made of glass, plastics, stainless steel, transparent resin, or the like. The printed wiring board 1 and the shield plate 4 are developed in a plane in the left, right, and depth directions of the drawing, between which a large number of light emitting elements are arranged in a uniform pattern as described later.

The composite semiconductor light emitting device A includes a Si diode 5 for protecting against static electricity as a submount device.
This is a combination with a light emitting element 6 of a blue light emitting LED mounted on the Si diode 5.

The Si diode 5 is an n-type silicon substrate 5
In this example, an n-electrode 5b is formed on the bottom surface of the substrate 5a to electrically connect to the wiring pattern 2a via the conductive paste 7 on the bottom surface. As shown in the schematic diagram of FIG. 3, the n-type silicon substrate 5a forms a mortar-shaped concave portion 5a-1 having a circular opening at the upper end side, and a part of the upper end surface around the concave portion 5a-1 is formed. Notch 5a-2 for passing wire 3
Is provided. Then, as shown in FIG. 2, the oxide film 5 is formed on the upper surface of the n-type silicon substrate 5a except for a part thereof.
c is formed, and p-type impurity ions are implanted by using a portion not covered with the oxide film 5c as a diffusion window, thereby forming n.
A p-type semiconductor region 5d is formed in a part of the silicon substrate 5a by diffusion.

On the upper surface of the n-type silicon substrate 5a, an n-electrode 8a and a p-electrode 8b including the oxide film 5c are formed by metal deposition. The n-electrode 8a is formed over the bottom occupying almost the left half of the concave portion 5a-1 in FIG. 2 and the inner peripheral surface rising therefrom, and is joined to a portion where the oxide film 5c is not formed and the n-type silicon substrate 5a is exposed. ing. On the other hand, the p-electrode 8b is formed in a region occupying substantially the right half of the concave portion 5a-1, and is joined to the p-type semiconductor region 5d diffused and formed in the n-type silicon substrate 5a.

The light emitting element 6 for emitting blue light is a device in which a GaN-based compound semiconductor is laminated on an insulating substrate and mounted on the upper surface of the Si diode 5 as a flip-chip type. This light-emitting element 6 has an n-side electrode 6b and a p-side electrode 6c formed on the respective surfaces of an n-type layer and a p-type layer laminated on a transparent sapphire substrate 6a by a vapor deposition method as in the example of FIG. The bump electrodes 6d and 6e are formed on the surfaces of the n-side electrode 6b and the p-side electrode 6c, respectively. Then, as shown in FIG. 2, the light-emitting element 6 is mounted so as to straddle the n-electrode 8a and the p-electrode 8b of the Si diode 5, and the n-electrode 6b and the p-electrode 6c are respectively connected to the p-electrode 8b and the p-electrode 8b. The wire 3 is mounted on the n-electrode 8a and bonded to the wiring pattern 2b of the printed wiring board 1 after being bonded to the p-electrode 8b. Further, after the bonding of the wire 3, the concave portion 5a is formed.
The entire inside of -1 is molded with a transparent or light-transmitting sealing resin 9 to protect the bonding portion between the light emitting element 6 and the wire 3.

In such a conductive structure around the light emitting element 6, since the light emitting element 6 is connected to the Si diode 5 with p and n having the opposite polarities, the light emitting element 6 is connected to the Si diode 5 with respect to the forward voltage. The resistance component of the n-type silicon substrate 5a acts as a protection resistor, and an overcurrent is released by a bypass opened by a voltage equal to or higher than the Zener breakdown voltage. Also,
With respect to the reverse voltage, the overcurrent is released by the bypass due to the forward characteristic of the Si diode 5. Therefore, it is possible to prevent an overcurrent from flowing to the light emitting element 6, thereby preventing the light emitting element 6 from being electrostatically damaged.

Here, the concave portion 5a-1 of the Si diode 5
Since the light emitting element 6 is formed in a mortar shape and the light emitting element 6 is dropped therein, the radiation power can be improved if the bottom surface and the inner peripheral surface of the concave portion 5a-1 are formed as light reflecting surfaces. That is, if the n-electrode 8a and the p-electrode 8b formed in the concave portion 5a-1 are deposited with Al or Ag having a high light reflectivity, the entire inside of the concave portion 5a-1 can be made a light reflecting surface. . Then, the light emitting element 6 is connected to the sapphire substrate 6.
In the case of the flip-chip type mounting in which a is directed to the shield plate 4, the light from the light emitting layer includes components that pass down and to the side in FIG.
The light can be collected in the light emitting direction by utilizing the light reflection by the surfaces of the electrodes 8a and 8b.

If the light emitting element 6 is assembled so that the center of the light emitting element 6 coincides with the center of the concave portion 5a-1, the light emitting element 6
Can be positioned at the center of the reflection surface formed by the n and p electrodes 8a and 8b. Therefore, the light from the reflecting surface can be converged in the light emitting direction of the light emitting element 6, and the convergence of the emitted light beam and the improvement of its power can be achieved. The light extraction efficiency is also improved by using the light-transmitting transparent sealing resin 9.

On the other hand, as shown in FIG. 2, the shield plate 4 is fixed so as to be in contact with the upper end of the Si diode 5. The shield plate 4 has a light-transmitting window 4a as a light-transmitting structure that matches the arrangement pattern of the composite semiconductor light-emitting elements A mounted on the printed wiring board 1. The light transmitting window 4a has a circular planar shape, and the center of the light transmitting window 4a substantially coincides with the optical axis of the light emitting element 6. The size of the light transmission window 4a is substantially the same as the opening diameter of the upper end of the concave portion 5a-1 of the Si diode 5,
It has a larger inner diameter than the light emitting element 6.

When the light emitting element 6 is energized, the Si diode 5 prevents the light emitting element 6 from being electrostatically damaged.
The durability is improved. Light emitted from the light emitting element 6 is emitted from the Si diode 5 that is substantially aligned with its optical axis.
The light transmission window 4 has the n and p electrodes 8a and 8b as reflection surfaces.
The radiated power is significantly improved by being collected on the side a and being combined with the light from the light extraction surface. In addition, since the light from the light emitting element 6 is irradiated from the light transmitting window 4a which is larger than the light transmitting element 6, the entire light emitting element 6 and the n and p electrodes 8a and 8 of the concave portion 5a-1 are formed.
Light from the entire reflecting surface using b can be extracted.

By making the size of the light emitting element 6 smaller than that of the light transmitting window 4a, light emitted from the entire sapphire substrate 6a serving as a main light extraction surface can be used as irradiation light to the recording medium. . Therefore, the light transmission window 4a
Even when light is shielded from light other than the above, light emission from the light emitting element 6 can be effectively used. Further, even if the light emitting element 6 is made smaller, the light from the reflecting surfaces of the n and p electrodes 8a and 8b can be collected, so that the irradiation power does not decrease as in the example of FIG.

FIG. 4 is a schematic view of an essential part showing an example in which a converging spherical lens 10 is incorporated between the light emitting element 6 and the light transmitting window 4a.

In addition, in each of the examples shown in FIG. 5 and subsequent figures including the example shown in FIG. 4, the same components as those shown in FIGS. 2 and 3 are designated by the same reference numerals, and detailed description thereof will be omitted.
The conductive structure between the Si diode 5, the light emitting element 6 and the printed wiring board 1 is exactly the same as that shown in FIG.

In FIG. 4, a spherical lens 10 is fixed on an upper surface of a sapphire substrate 6a of a light emitting element 6 conductively mounted on a Si diode 5 by an adhesive 10a so that the center is located on the optical axis of the light emitting element 6. Have been. In order to incorporate this spherical lens 10, the distance between the printed wiring board 1 and the shield plate 4 is made wider than in the example of FIG. 2, and the light transmission window 4a is located at the optical axis of the light emitting element 6 as in the previous example. An assembly that aligns with the assembly.

By providing such a spherical lens 10 in the optical path, even if the upper end of the Si diode 5 is not abutted against the lower surface of the shield plate 4, the light emission from the light emitting element 6 and the inside of the recess 5 a-1 can be achieved. The light reflected from the reflective surfaces of the n and p electrodes (8a, 8b: see FIG. 2) located at the position (1) can be collected and irradiated from the light transmission window 4a. The resolution of the written image can be further improved by forming the shape of the spherical lens 10 so that the irradiation light beam is focused on the recording paper.

FIG. 5 shows the light transmission window 4a of the shield plate 4.
FIG. 3 is a longitudinal sectional view showing an example in which is a lens structure.

In the example of FIG. 5A, the light transmitting window 4a incorporates a plurality of glass fibers 4b, and a convex lens 4c is formed by assembling the glass fibers 4b. (B) of the same figure shows a case where a plurality of glass fibers 4d are similarly incorporated to form a concave lens 4e.

By forming the light transmitting window 4a with the convex lens 4c or the concave lens 4e in this manner, it becomes possible to condense light corresponding to the distance from the surface of the shield plate 4 to the recording paper. Resolution can be improved.

FIG. 6 is a schematic diagram showing another configuration for promoting light emission from the light emitting element 6. In FIG.

FIG. 6A shows a sapphire substrate 6a of the light emitting element 6 in place of the sealing resin 9 in the configuration shown in FIG.
This is an example in which the light-transmitting resin 11 is laminated on the surface of the sapphire substrate 6a, as compared with the case where the entire recess 5a-1 of the Si diode 5 is sealed with resin as in the example of FIG. Can be raised.

FIG. 6 (b) shows the light transmitting window 4a of the shield plate 4 as a filling layer of the light transmitting resin 12a, and the entire surface including the surface of the light transmitting resin 12a is covered with the light transmitting sheet 12b. It was done. Light transmitting sheet 12b
Can be a thin film of glass or synthetic resin. Also in this example, it is possible to improve the efficiency of extracting light emitted from the light emitting element 6. Also, even if a hole is formed in the shield plate 4 and the light-transmitting resin 12a is filled therein to form the light-transmitting window 4a, it is sealed by the light-transmitting sheet 12b, so that dust and the like from the outside can be prevented. Penetration is prevented, and the integrity of the light emitting element 6 is improved.

The light transmitting window 4a is provided on the shield plate 4.
In such a case that a hole is formed, the light transmitting sheet 12
It is a matter of course that the hole may be closed by providing only b.

As described above, various configurations can be applied as a configuration for promoting light extraction from the light emitting element 6. The light emitting element 6 having the spherical lens 10 shown in FIG.
4e or a combination with the configuration of FIG. 6 (b). Further, the light emitting element 6 in which the light transmitting resin 11 of FIG. 6A is laminated is replaced with the lenses 4c and 4 of FIGS. 5A and 5B.
It can also be combined with e. In any case, it is possible to encourage the emission of light from the light emitting element 6, and a combination of optimal configurations according to use conditions and the like may be used.

FIG. 7 is a schematic diagram showing a configuration in which heat radiation from the printed wiring board 1 is promoted to suppress the thermal effect on the light emitting element 6 and the radiation power can be maintained.

FIG. 7A shows an example in which the material of the base 1a of the printed wiring board 1 is aluminum having a high thermal conductivity, and a plurality of fins 1c having an uneven shape are formed on the lower surface thereof. By providing the fins 1c in this manner,
The heat from the light emitting element 6, which becomes high temperature during light emission, is transferred from the insulating film 1b to the base 1a and is radiated from the fins 1c.
Therefore, the temperature rise of the light emitting element 6 is suppressed, and the radiation power can be prevented from lowering.

FIG. 7B shows a heat-dissipating fixed grease 1 between the printed circuit board 1 and a fixed member 13 for mounting the printed wiring board 1.
This is an example where 3a is interposed. The fixing member 13 is disposed inside the writing device for mounting the printed wiring board 1, and is made of metal. The surface roughness of the bottom surface of the base 1a of the printed wiring board 1 and the surface roughness of the fixing member 13 are made relatively small, and the surface area when joining them with the heat-dissipating fixing grease 13a is increased. The heat transfer area from the base 1a to the fixing member 13 can be increased by such a relationship of the surface roughness, and heat transfer from the base 1a to the fixing member 13 is promoted by the heat-dissipating fixing grease 13a. Therefore, as in the example of FIG. 7A, it is possible to suppress the temperature of the light emitting element 6 from rising, and to maintain the radiation power at a stable level.

Note that, in each of the examples of FIGS. 4 to 7, as shown in the example of FIG.
The radiation power can be increased by using the n and p electrodes 8a and 8b formed in a-1 as the reflection surface.

FIG. 8 is a longitudinal sectional view of a main part showing another example, in which a shield plate is eliminated and a printed wiring board is also used.

In FIG. 8, a light transmitting window 21a as a light transmitting portion is provided on a printed wiring board 21 having a conductor pattern formed on the lower surface side, and a mount for disposing the light emitting element 6 corresponding to the light transmitting window 21a. The block 22 is fixed to the lower surface of the printed wiring board 21.

The mount block 22 is a silicon substrate 22
a is made of a material, and a mortar-shaped concave portion 22b is formed inside similarly to the example of the Si diode 5 of FIG. Then, an oxide film 22c is formed on the surface of the concave portion 22b, and a pair of electrodes 22d and 2d are formed on the surface of the oxide film 22c.
2e is provided. These electrodes 22d and 22e are formed by developing from the inner peripheral surface to the bottom of the concave portion 22b.
By fixing the mount block 22 to the printed wiring board 21 with the conductive adhesive 23, the conductive pattern of the printed wiring board 21 is conducted. And the electrode 22
d and 22e are the p-side and n-side electrodes 6c of the light emitting element 6,
The light-emitting element 6 is mounted in the recess 22b by making the bumps 6b conductive by the bump electrodes 6e and 6d, respectively.

Also in this configuration, the light emitting element 6 is smaller than the light transmission window 21a and the electrodes 22d and 22d around the light transmission window 21a.
The light emission intensity can be increased by the reflection surface using 22e. In addition, since the printed circuit board 21 and the mount block 22 are combined without a shield plate, the thickness can be reduced as compared with the configurations of the examples of FIGS.

[0065]

According to the present invention, all of the light emitted from the light extraction surface of the light emitting element can be emitted from the light transmitting structure, and at the same time, the light leaking from other than the light extraction surface can be reflected by the reflection means. Even if it is small, the amount of light irradiation necessary for writing an image can be obtained. Therefore, the cost can be reduced by downsizing the light emitting element.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a light emitting device for image writing according to the present invention.

FIG. 2 is a longitudinal sectional view showing a main part of another example of the image writing light emitting device of the present invention.

FIG. 3 is a schematic perspective view of a composite semiconductor light emitting element included in the light emitting device of FIG. 2;

FIG. 4 is a longitudinal sectional view showing a main part of a light emitting device having a spherical lens on an upper surface of a light emitting element.

FIG. 5 is a schematic longitudinal sectional view showing an example of a light emitting device using a glass fiber lens.

6A is a vertical sectional view of another example in which a light-transmitting resin is laminated on the light-emitting element, and FIG. Schematic diagram of an example in which a light-transmitting resin is filled in a transmission window

7A and 7B are examples in which radiation power is suppressed by heat radiation from a printed wiring board, and FIG. 7A is a longitudinal sectional view showing an example in which a fin is formed on a base of the printed wiring board; FIG. Longitudinal sectional view showing an example of applying fixed grease to

FIG. 8 is a longitudinal sectional view showing an example in which a printed wiring board and a mount block are combined.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed wiring board 1a Base 1b Insulating film 1c Fin 2a, 2b Wiring pattern 3 Wire 4 Shield plate 4a Light transmission window 4b, 4d Glass fiber 4c, 4e Lens 5 Si diode (submount element) 5a n-type silicon substrate 5a-1 Recess 5a-2 notch 5b n-pole 5c oxide film 5d p-type semiconductor region 6 light emitting element 6a sapphire substrate 6b n-side electrode 6c p-side electrode 6d, 6e bump electrode 7 conductive paste 8a n-electrode 8b p-electrode 9 sealing resin 10 Spherical lens 10a Adhesive 11 Light transmissive resin 12a Light transmissive resin 12b Light transmissive sheet 13 Fixing member 13a Fixed grease 21 Printed wiring board 21a Light transmissive window 22 Mount block 22a Silicon substrate 22b Recess 22c Oxide film 22d, 22e Electrode 23 Conductive The adhesive 31 printed wiring board 32a, 32b wiring patterns 33 light emitting elements 33a substrate 33b n-type layer 33c p-type layer 33d n electrode 33e p electrode 33f, 33 g wire 34 shield plate 34a light transmitting window 34b mask pattern 35 resin layer

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kenichi Koya 1-1, Komachi, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd. F-term (reference) 5F041 AA04 CB27 DA01 DA07 DA14 DA20 EE11 EE21 FF13 FF16

Claims (12)

[Claims] 1. A wiring board, a light emitting element conductively mounted on the wiring board, a shield plate disposed to face a light emitting direction of the light emitting element, and the shield facing a light extraction surface of the light emitting element. A light transmitting structure provided on a plate, wherein the light transmitting structure has a shape having a size including an entire outer periphery of a light extraction surface of the light emitting element; A light-emitting device for writing an image, comprising a reflecting means for reflecting light leaking from a portion other than the light extraction surface toward the light transmitting structure. 2. A wiring board, a submount element conductively mounted on the wiring board, a light emitting element conductively mounted on the submount element, and a shield plate disposed so as to face a light emitting direction of the light emitting element. And a light transmitting structure provided on the shield plate facing the light extraction surface of the light emitting element, wherein the light transmission structure covers the entire outer surface of the light extraction surface of the light emitting element. The light emitting device for image writing, wherein the submount element includes a reflection unit configured to reflect light leaking from a portion other than the light extraction surface toward the light transmission structure. 3. A wiring board partially formed with a light transmitting structure, a mount block having a concave cross-section and having a concave portion facing one surface side of the wiring substrate and conductively fixed therein, and a conductive block in the concave portion of the mount block. A light emitting element having a light extraction surface fixed to face the light transmission structure, wherein the light transmission structure has a shape including a whole outer periphery of the light extraction surface of the light emission element, and a concave portion of the mount block. A light-emitting device for writing an image, comprising a reflecting means for reflecting light leaking from a portion other than the light extraction surface toward the light transmitting structure. 4. The light emitting device for image writing according to claim 1, wherein an optical axis of said light emitting element and a core of said light transmitting structure are substantially aligned. 5. The light-transmitting resin according to claim 1, wherein a light-transmitting resin is filled between the light-transmitting structure and a portion where at least a light extraction surface of the light-emitting element faces the light-transmitting structure. The light emitting device for image writing according to the above. 6. A spherical lens for condensing light from the light extraction surface and forming an optical path to the light transmission structure between the light extraction surface of the light emitting element and the light transmission structure. The light-emitting device for image writing according to claim 1. 7. The wiring board includes a metal base, an insulating film laminated on the base, and a wiring pattern formed on a surface of the base, and a heat radiation fin provided on a bottom surface of the base. Item 7. An image writing light emitting device according to any one of Items 1 to 6. 8. The wiring board comprises a metal base mounted and fixed on a fixing member on the device side, an insulating film laminated on the base, and a wiring pattern formed on the surface thereof.
The light-emitting device for image writing according to any one of claims 1 to 6, wherein the surface roughness of the base and the fixing member is reduced, and the base member and the fixing member are joined by a heat-dissipating fixing grease. 9. The image writing light emitting device according to claim 1, wherein said light transmitting structure is a hole formed in said shield plate. 10. The light-emitting device for image writing according to claim 9, wherein a light-transmitting resin is filled inside the hole of the light-transmitting structure. 11. The light-emitting device for image writing according to claim 9, wherein a light-transmitting coating layer is formed so as to include the holes of the light-transmitting structure. 12. The light emitting device for image writing according to claim 9, wherein a lens for condensing light from said light emitting element is provided in a hole of said light transmitting structure.