JPH09270537A - Photoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply obtain a uniform optical characteristic, without adding a new unit, by coloring a protector for protecting an optical semiconductor element according to its optical characteristic to add a screen-filmy function to the protector. SOLUTION: Packages 102 contg. optical semiconductor elements i.e., light emitting elements are disposed like a matrix on a common matrix substrate 103 and have light-permeable protectors 101 made of a light permeable material e.g. epoxy resin. The protectors have different color densities. The optical output is measured when the light emitting elements are mounted in the package 102 and electrically wired. The elements providing a high optical output are combined with hyperchromic protector 101 and those providing a low output are combined with a hypochromic protector, thus the intensity of the light taken out from each emitting element through the protector 101 is made const. to reduce the dispersion of the optical characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LED display device using two or more optical semiconductor elements, an optical printer head,
The present invention relates to a photoelectric conversion device used for line sensors, image scanners, and the like, and more particularly to a photoelectric conversion device in which variations in optical characteristics among individual optical semiconductor elements are small and semiconductor characteristics are stable.

[0002]

2. Description of the Related Art There are various sensors, displays and the like in which two or more light emitting elements and / or light receiving elements which are optical semiconductor elements are used and arranged in an array or a matrix. Specifically, RGB is used as the light emitting element of the photoelectric conversion device.
An LED display device is formed by using three or more light emitting diodes of three colors (red, green, blue). In the LED display, each light emitting diode is arranged in a desired shape such as a matrix on a substrate. The LED display can perform full color display by combining the emission colors of the respective light emitting diodes. When all the light emitting diodes corresponding to RGB are turned on as one picture element, white can be displayed, and red and green can display yellow and green and blue can display cyan. Further, the brightness of each light emitting diode can be adjusted to display various emission colors.

In a photoelectric conversion device constructed by using a plurality of such optical semiconductor elements, a protector is provided to protect the optical semiconductor elements contained therein from moisture, dust and external force from the external environment. . As the protector, a transparent or uniformly colored translucent one is used in order to maintain the optical characteristics of the optical semiconductor element. Further, it is conceivable that the protective body has a colored gradient (shade) formed therein, or that the protective body has a different colored density for each emission wavelength such as RGB to improve the contrast.

[0004]

However, the characteristics of individual optical semiconductor elements are not taken into consideration in any case. When manufacturing a plurality of optical semiconductor elements, there are subtle variations in optical characteristics for each semiconductor wafer or each portion of the semiconductor wafer due to various conditions such as a difference in impurity diffusion amount during manufacturing of a semiconductor wafer and temperature unevenness. In addition, when dicing the package, variations such as brightness and light quantity distribution occur. This variation appears as it is as variation in each part of the photoelectric conversion device. That is, if there are variations in the optical characteristics of the used optical semiconductor element, the variations directly affect the variations of each part of the photoelectric conversion device. Such variations in light characteristics cause color unevenness or the like when used in an LED display. Therefore, it is necessary to select and use the optical semiconductor element according to the optical characteristics, and there is a problem that the yield is extremely low. In particular, when a photoelectric conversion device is configured by using an extremely large number of optical semiconductor elements such as a display, it is necessary to make the light emission characteristics of all the optical semiconductor elements uniform, resulting in extremely poor productivity.

It is also conceivable to provide a current adjusting means so as to measure the variation in order to correct the variation of the optical semiconductor element and to apply the power individually to each optical semiconductor element.
However, such an electrical correction means not only causes complication associated with the addition of new equipment, but also increases the heat generation amount of the entire photoelectric conversion device by using the means. When the heat radiation amount of the optical semiconductor element increases, a new problem arises that the optical semiconductor characteristics of the optical semiconductor element become unstable.

Therefore, in the present day when more excellent optical characteristics are required, the photoelectric conversion device having the above configuration is not sufficient, and further improvement in characteristics is required. In view of the above problems, the present invention adds a new device by coloring a protective body for protecting an optical semiconductor element in accordance with the optical characteristics of the optical semiconductor element and providing the protective body with a light-shielding filter function. It is an object of the present invention to provide a photoelectric conversion device having uniform light characteristics relatively easily.

[0007]

SUMMARY OF THE INVENTION The invention of the present application comprises two
What is claimed is: 1. A photoelectric conversion device comprising the above-mentioned optical semiconductor elements, each of which has a light-transmitting protective body for protecting the light-semiconductor element. The output section is a photoelectric conversion device that is colored so that the respective light output and / or light input characteristics are close to each other corresponding to the two or more optical semiconductor elements.

Further, the photoelectric conversion device is colored by the coloring agent contained in the light-transmitting protective body, and is also a photoelectric conversion device in which the coloring is achromatic color of white, black or gray. Furthermore, the coloring is a photoelectric conversion device in which the translucent protective body is discolored.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventor has conducted various experiments,
It has been found that the light characteristics are uniform and stabilized by coloring the light-transmitting protective body of the photoelectric conversion device according to the light characteristics of each optical semiconductor element and imparting a function like a light-shielding filter, and based on this, the present invention It came to be done. That is, in the photoelectric conversion device of the present invention, the translucent protective body that protects the optical semiconductor element is colored according to the optical characteristics of each optical semiconductor element, and as a result, there is no variation in each part. Is something that can be done. This photoelectric conversion device
After the electrical connection of the optical semiconductor element is completed, it is obtained by measuring the light characteristics and adjusting the light transmittance of the light-transmitting protective body so as to obtain the desired characteristics. Therefore, it is possible to alleviate the non-uniformity of the characteristics at the time of forming the element and also alleviate the non-uniformity of the characteristics due to the defective electrical connection. The photoelectric conversion device of the present invention will be described below with reference to the drawings.

FIG. 1 shows an LED of the photoelectric conversion device of the present invention.
It is a schematic plan view of the display applied to the matrix. Packages including light emitting elements which are optical semiconductor elements are arranged in a matrix on a matrix substrate 103 which is a common substrate. Further, the package accommodates a translucent protective body 101 made of a translucent material such as epoxy resin. Different shades of light (light shielding) are attached to the translucent protective body 101. The light and shade of the color of the light-transmitting protective body 101 can be measured with the light emitting element mounted inside the package and electrically connected. A light-transmitting protector of dark color is combined with a light-emitting element having a large light output, and a light-transmitting protector of light color is combined with a light-emitting element having a small light output. The darker the color of the translucent protective body, the lower its transmissivity. Therefore, by changing the shade of the color of the light-transmitting protective body according to the output of the light-emitting element, the light extracted from each light-emitting element to the outside of the light-transmitting protective body can be made constant. This makes it possible to obtain a photoelectric conversion device with extremely small variations in light emission from part to part.

Therefore, even if an electrical correction circuit is not provided, the light emitting characteristics can be made uniform by an extremely simple structure in which the coloring of the translucent protective body is changed for each part. Further, as compared with the case where the light emission characteristics are made uniform by an electric circuit, more stable light characteristics can be obtained without heat generation from the correction circuit. In particular, when a light emitting diode is used in a photoelectric conversion device, the characteristics of the light emitting element may change due to heat, and the light emitting diode itself may generate heat, which may cause heat dissipation.

FIG. 2 shows a cross section taken along the line AA which is a part of the photoelectric conversion device of FIG. Hereinafter, the photoelectric conversion device of the present invention will be described in detail with reference to FIG. Package bottom 1
A light-emitting element 201 as an optical semiconductor element is fixed to 02 by die bonding. Next, the package electrode 203 and the light emitting element 2
The electrode on 01 is electrically connected by a wire bond connection of the metal wire 202 or the like. In this way, the light output of each light emitting element is individually measured using an optical measuring device in the state where a plurality of light emitting elements are formed on the matrix substrate 103. A colorant-containing resin having various coloring concentrations is prepared so that a light-transmitting protective body of an optical semiconductor device having a higher light output can have a darker color depending on the individual light output. The translucent protective body 101 before curing is potted in the concave portion of the package 102. The coloring is preferably performed by adding a coloring agent such as a dye and / or a pigment to a transparent epoxy resin and mixing and stirring. The color density can be easily changed by this addition amount. The electrical connection between the package electrodes 203 and the electrodes 204 of the matrix substrate 103 is performed by the translucent protective body 10.
1 may be formed before or after the formation. By performing soldering or the like between the electrodes, a photoelectric conversion device in which the light emitting elements are arranged in a matrix can be formed.
With such a structure, the photoelectric conversion device of the present invention can have extremely small variations in light input / output in each part, and the yield is improved.

Although the present invention has been described above by taking the photoelectric conversion device using the LED, which is a light emitting element, as an example, it is obvious that the present invention can be applied to other photoelectric conversion devices such as photosensors and solar cells. Further, the number of the optical semiconductor elements of the present invention may be two or more, and various types such as a long shape in which the optical semiconductor elements are arranged in a line, a zigzag shape, or a lattice shape can be selected. Hereinafter, each configuration of the present invention will be described in detail.

(Optical semiconductor element 201) As the optical semiconductor element 201 used in the present invention, a light receiving element for converting light into electricity or a light emitting element for converting electricity into light is used.
As the light receiving element, a G formed by utilizing the liquid crystal growth method
e, Si, InAs, CdS or the like using a single crystal semiconductor or a polycrystalline semiconductor, microcrystals formed by various CVD methods using energy such as plasma, heat, light, Si, SiC of an amorphous semiconductor, An optical sensor using a non-single crystal semiconductor such as SiGe, a solar cell, or the like is used. Examples of the semiconductor structure include a homostructure and a heterostructure having a PN junction and a PIN junction. The light receiving wavelength of the light receiving element can be selected depending on the semiconductor material and the degree of mixed crystal thereof. A light-receiving element can be formed by forming a semiconductor of the above-described structure in a desired size on a glass, heat-resistant resin or stainless steel substrate and making electrical connection. The electrodes of the light receiving element are Al and A formed by sputtering or vacuum deposition.
Various metals such as g and Au, and n ⁺ semiconductors can be used.

On the other hand, as a light emitting element, a liquid phase growth method or MO
GaAlN, ZnS, ZnS on the substrate by the CVD method etc.
e, SiC, GaP, GaAlAs, AlInGaP,
An LED, LD, or the like in which a semiconductor such as InGaN, GaN, or AlInGaN is formed as a light emitting layer is used. Examples of the semiconductor structure include a homo structure, a hetero structure, and a double hetero structure having a MIS junction and a PN junction. The emission wavelength can be selected from ultraviolet light to infrared light depending on the material of the semiconductor layer and its degree of mixed crystal.
Further, the light emitting layer may have a single well structure or a multiple well structure in order to have a quantum effect.

After the semiconductor wafer thus obtained, on which various electrodes are formed on the semiconductor, is directly full-cut by a dicing saw in which a blade having a diamond edge is rotated, or a groove having a width wider than the edge width is cut. (Half cut), the semiconductor wafer is broken by external force. Alternatively, an extremely thin scribe line (meridian line) is drawn on the semiconductor wafer by, for example, a grid pattern by a scriber in which the diamond needle at the tip moves back and forth in a straight line, and then the wafer is divided by external force to cut the semiconductor wafer into chips to form light emitting elements. Let The thus-formed optical semiconductor element can be directly arranged on the substrate and electrically connected, but it can also be electrically connected to the substrate together with the package after the optical semiconductor element is put in the package. .

The package 102 is for fixing an optical semiconductor element inside and accommodating a translucent protective body for protecting the optical semiconductor element. Therefore, it is required to have good adhesiveness to the translucent protective body and higher rigidity than the translucent protective body. Further, in order to improve the adhesiveness with the translucent protective body and direct the force exerted by the translucent protective body at the time of thermal expansion to the outside, the cylindrical portion may be shaped like a sloping pot that expands toward the outside. Furthermore, in order to accommodate and use an optical semiconductor element having a spectral characteristic in visible light, it is preferable that the optical semiconductor element is colored in order to function as a light shielding property. Further, it is desired to have an insulating property in order to electrically cut off the optical semiconductor element from the outside. Further, when the package is affected by heat from an optical semiconductor element or the like, it is preferable that the package has a small coefficient of thermal expansion in consideration of adhesion with a protective body. The inner surface of the package can be embossed to increase the adhesion area, or plasma-treated to improve the adhesion with the protector.

Resins such as polycarbonate resin, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), ABS resin, epoxy resin, phenol resin, acrylic resin and PBT resin can be used for such a package. When the optical semiconductor element is directly arranged on the package, thermosetting resin or the like can be used. Specifically, an epoxy resin, an acrylic resin, an imide resin, or the like can be given.

(Base 103) The base 103 used in the present invention is for disposing the optical semiconductor element 201 or the package 102 having an optical semiconductor therein. The optical semiconductor elements 201 can be arranged in various shapes such as a line shape, a stripe shape, and a matrix shape, as desired. Further, the base may be used not only as the arrangement of the optical semiconductor elements but also as a substrate of a circuit for driving the optical semiconductor elements. The substrate is preferably one having high mechanical strength and little thermal deformation. Specifically, a substrate made of ceramics, glass, various resins or the like on which a conductor such as copper foil is formed can be preferably used.

(Translucent Protective Body 101) The translucent protective body 101 used in the present invention protects each optical semiconductor element and wires for electrical connection thereof from external force and moisture, and It is provided to make the characteristics of the optical semiconductor element uniform and uniform. Therefore, the light-transmitting protective body and the optical semiconductor element may be formed in close contact with each other, or may not be in close contact with the optical semiconductor element for heat dissipation and stress relaxation. In order to make the characteristics of each optical semiconductor element uniform and uniform, it is necessary to control the transmittance of the translucent protective body at least in the optical input / output section in a range that affects the optical characteristics of each optical semiconductor element. it can. Specific examples of the material of such a translucent protective body include epoxy resin, urea resin,
A resin having excellent weather resistance such as a silicone resin, a fluororesin, or a polycarbonate resin is preferably used.

(Coloring of Translucent Protective Body) Coloring of the translucent protective body of the present invention is carried out so as to control light which influences the optical characteristics of the optical semiconductor element so as to bring the respective optical characteristics closer to each other. is there. The change in the light transmittance due to coloring can be controlled by changing the color of the light-transmitting protective body by irradiating the light-transmitting protective body with heat energy or ultraviolet rays and the irradiation amount. In this case, care must be taken not to damage the optical semiconductor element due to the irradiation of heat energy or ultraviolet rays. In the case of using a laser beam, after forming a panel of the light-transmitting protective body on the optical semiconductor element, the portions corresponding to the individual optical semiconductor elements can be subjected to stepless color control.

The change in light transmittance due to coloring can also be controlled by changing the concentrations of various dyes and / or pigments as coloring agents. When a colorant is used, it can be dispersed in various ratios in the light-transmitting protective body as desired, or can be applied and colored in a desired amount on the light-transmitting protective body using an inkjet coating device. .

The light-transmitting protective body may be divided into two or more layers as shown in FIG. 3, and only one of the layers may be colored. You can make it a multi-layer structure of layers with different transmittance,
The concentration of the coloring agent may be increased or decreased as the optical semiconductor element is approached. Furthermore, in the case of dividing into two or more layers, a colorant can be enclosed in the middle. When the colorant is mixed into the translucent protective body, it can be formed by mixing and stirring the colorant in the raw material of the translucent protective body, and then pouring it into the package and curing it.

Coloring of the translucent protective member is selected according to the optical characteristics of the optical semiconductor element and desired optical characteristics. Specifically, in the case of an LED matrix display using a blue light emitting element or a line sensor for reading blue, it is possible to color blue in addition to achromatic color of white, black or gray. . Hereinafter, specific examples of the present invention will be described in detail, but the invention is not limited thereto.

[0025]

【Example】

Example 1 A gallium nitride semiconductor having a PN junction is formed on a sapphire substrate by using the MOCVD method as an optical semiconductor device. After that, a P-type electrode and an N-type electrode are formed on the semiconductor by using a sputtering apparatus, and the sapphire substrate is individually divided to obtain the light emitting element 201.
Next, the die 102 is die-bonded in the package 102, and the package electrode 203 and the optical semiconductor element 2 are formed by the gold wire 202.
Wire bonding with each electrode of 01. As shown in FIG. 1, this is placed on a substrate 101 on which a conductive pattern is formed.
× 6 pieces are arranged in a matrix and electrically connected by solder to form a photoelectric conversion device.

After that, each optical semiconductor element of the photoelectric conversion device was measured by an optical measuring device and divided into four stages. The darkest light emitting element is a translucent protection in which the translucent protective material is formed of an epoxy resin to which a black colorant is not added, and the concentration of the black colorant is changed by 10% in inverse proportion to the progressively brighter color. Let the body form. The thus-formed photoelectric conversion device has no change in emission color tone and can improve the emission uniformity by about 25% or more as compared with before measurement.

Example 2 The translucent protective body was divided into two layers as shown in FIG. 3, and a black colorant was colored only on the surface of the lower layer 302 so that the characteristics of each optical semiconductor element were close to each other. Other than that was formed similarly to Example 1. For simplification, the coloring is adjusted in four steps by using colorants having three kinds of concentrations as in Example 1. Similar to Example 1, the light emission uniformity can be improved by about 25% or more.

[Embodiment 3] As shown in FIG. 4, the light-transmissive protective member is subjected to stepless change of irradiation time with a laser 402 of 20 W and heat is applied to the surface 40 of the light-transmissive protective member.
A photoelectric conversion device was constructed in the same manner as in Example 1 except that the color of 1 was changed steplessly. The emission uniformity can be better than that of the first embodiment.

[Embodiment 4] As shown in FIG.
The optical semiconductor element formed in the same manner as above is formed on a transparent substrate such as sapphire, and is applied to a photoelectric conversion device in which the transparent substrate is provided on the main light emitting surface side in a flip chip mounting mode. An underfilling paste made of a translucent epoxy resin, which is colored in three steps and uncolored, is formed in four steps according to the characteristics of the optical semiconductor element. Similar to Example 1, the light emission uniformity can be improved by about 25% or more.

[0030]

As described above, with the construction of claim 1 of the present invention, the output is actually measured, and the color density of the light-transmitting protective body is determined based on the measurement result to adjust the output. The optical output is selected at the stage of a single optical semiconductor element, and the allowable range of variations in the optical characteristics of the single optical semiconductor element is remarkably widened compared to the case where only optical semiconductor elements having suitable optical characteristics are mounted, and the yield is improved. Further, since the optical characteristics can be matched after being mounted on the package, it is possible to prevent the optical characteristics from varying due to variations in the package size and reflectance.

With the structure of claim 2 of the present invention, the optical characteristics can be easily made uniform by using only the colorant content changed at the time of forming the translucent protective material.

By adopting the constitution of claim 3 of the present invention, it is possible to prevent the change in color tone due to the color shading.

With the configuration of claim 4 of the present invention, coloring can be adjusted steplessly.

[0034]

[Brief description of drawings]

FIG. 1 is a plan view of an LED matrix according to an embodiment of the present invention.

2 is a partial cross-sectional view taken along the line AA of the LED matrix of FIG.

FIG. 3 is a partial cross-sectional view of another embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing a coloring process of still another embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of another embodiment of the present invention.

[Explanation of symbols]

 101 ... Translucent protective body 102 ... Package 103 ... Substrate 201, 501 ... Opto-semiconductor element 202 ... Electrical connection member wire 203 ... Package electrode 204 ... Matrix Substrate electrode 301: first layer translucent protective body 302 ... second layer translucent protective body 401 ... discolored portion of translucent protective body 402 ... laser irradiation nozzle 502 ... Underfilling paste 503 ... bumps

Claims (4)

[Claims] 1. A photoelectric conversion device having two or more optical semiconductor elements arranged on a substrate and having a translucent protective body for protecting the optical semiconductor elements, wherein: At least the light input / output unit to / from the optical semiconductor element is colored so that each light output and / or light input characteristic corresponds to the two or more optical semiconductor elements. 2. The photoelectric conversion device according to claim 1, wherein the coloring is performed with a coloring agent contained in the light-transmitting protective body. 3. The photoelectric conversion device according to claim 1, wherein the coloring is an achromatic color such as white, black, or gray. 4. The photoelectric conversion device according to claim 1, wherein the coloring is performed by changing the color of the translucent protective body.