JPH0274080A - LED chip and its manufacturing method - Google Patents

Abstract

PURPOSE:To enable the formation of an image which is high in quality and free from a periodic fluctuation in density in an auxiliary scanning direction when the image is recorded by a method wherein two or more P-N junction planes are provided being separated and independent from each other, and each P-N junction has two regions, one is continuous and the other is divided into parts which are separate and independent from each other. CONSTITUTION:A cut groove 75 is provided to a central part of an N region of an LED chip 74, whereby the N region is divided completely into two. That is, a junction plane of a P region with an N region is formed into two parts which are independent from each other, and the LED chip 74 is a single chip provided with two light emitting sections 74A and 74B independent from each other. The pitch between the light emitting sections 74A and 74B is formed equal to an auxiliary scanning pitch. By this setup, a mounting position (pitch between color light emitting sections) is made to improve in accuracy without degrading cost and productivity and the light emitting sections can be accurately mounted at a specified pitch (equal to auxiliary scanning pitch) between them, and a high quality image free from a periodic fluctuation in density in an auxiliary scanning direction can be formed when the image is recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an LED chip used in an image recording device or the like that scans light based on image information and records an image on a recording material, and a method for manufacturing the same.

[Conventional Technique #] A recording material is wound around the outer circumference of a recording drum, a light source is activated based on image information, and the recording drum is rotated to perform main scanning and sub-scanning, thereby recording an image on the recording material. There is an image recording device.

This type of image recording device uses a so-called exposure head in which a light emitting element such as an LED is arranged on a stem as a light source, and the light emitted by the light emitting element in this exposure head is focused by a lens. irradiates the recording material.

By the way, in order to obtain a color image, for example, light sources of three different colors (for example, the three primary colors of Y and MSC) are required.
There is an exposure head in which LEDs corresponding to these three colors are arranged on a single stem in the main scanning direction.

In this exposure head, each LED is arranged on a stem at predetermined intervals in the main scanning direction, and furthermore, a single condenser lens is arranged in front of each LED. The light emitted from each LED is condensed by a condenser lens and irradiated onto the recording material. Therefore, compared to an exposure head in which three color light sources of Y, M, and C are configured independently, the number of parts is reduced and the shape is compact.

Furthermore, some exposure heads have LEDs corresponding to three colors arranged in multiple rows in the sub-scanning direction. With this type of exposure head, multiple rows of pixels can be exposed simultaneously by -degree main scanning, and the time required to record an image can be significantly reduced compared to an exposure head with LEDs arranged in only one row. There are advantages such as

[Problems to be Solved by the Invention] By the way, in an exposure head in which LEDs corresponding to three colors are arranged in multiple rows in the sub-scanning direction, the mounting of each LED is determined by the position and the pitch between LEDs of the same color and the sub-scanning direction. If the scanning pitch), the amount of light emitted, the diameter of the emitted beam, etc. are not uniform and accurate, periodic density fluctuations (so-called unevenness) will occur in the sub-scanning direction and the quality of the image will deteriorate.

In particular, if the mounting position of each LED (pitch between LEDs of the same color) is shifted from the sub-scanning pinch, this will have a large effect, and periodic density fluctuations (unevenness) in the sub-scanning direction will be noticeable. The quality of the image deteriorates significantly.

In this case, it is not easy to improve the positional accuracy and accurately mount each LED at a predetermined pitch (the same pitch as the sub-scanning pitch), and the cost is high.

The present invention takes the above facts into consideration, and allows installation to be done at the correct position (pitch between light-emitting parts of the same color) without deteriorating cost or productivity.
It can be mounted accurately at a predetermined pitch (the same pitch as the sub-scanning pitch) with improved accuracy, and this prevents periodic density fluctuations (unevenness) in the sub-scanning direction when recording images on recording materials. The purpose is to obtain an LED chip that can form a high-quality image, and a method for manufacturing the same.

[Means for Solving the Problems] In the LED chip according to the present invention, one of the integrally formed P region and N region is continuous,
The other region is separated into a plurality of independent and spaced apart regions, and includes a plurality of independent PN junction surfaces that are spaced apart from each other.

Further, the method for manufacturing an LED chip according to the present invention
LEDs are manufactured by cutting a wafer and dividing it into multiple chips.
A method for manufacturing a chip, wherein when dividing the chip into the plurality of chips, either one of the P region and the N region of a single chip is completely cut away, and these regions are separated from each other to form a plurality of independent chips. It is characterized by forming a plurality of independent PN junction surfaces spaced apart from each other within a single chip.

[Function] In the LED chip of the present invention, since a plurality of junction surfaces between the P region and the N region are formed independently of each other, this LED chip has a plurality of independent depletion regions (light emitting parts) in a single chip.
It will be equipped with the following.

In this case, the pitch between the plurality of depletion regions (light emitting parts) (in other words, the pitch between the bonding surfaces) is a predetermined pitch (the same pitch as the sub-scanning pitch) at the time of manufacturing the LED chip.
It can be formed accurately and accuracy is also improved.

When recording an image on a recording material using this LED chip, a plurality of light-emitting parts are arranged along the sub-scanning direction, and light from the plurality of light-emitting parts is used in main scanning and sub-scanning. An image is recorded on the recording material.

In this case, in the past, multiple independent light sources were each mounted independently, which made it difficult to accurately mount them at a predetermined pitch (the same pitch as the sub-scanning pitch), and this led to high costs. In the LED chip according to the present invention, since the plurality of independent light emitting parts can be formed accurately at a predetermined pitch (the same pitch as the sub-scanning pitch) at the time of manufacturing the LED chip, the LED chips can be arranged along the sub-scanning direction. The pitch between the plurality of light emitting parts does not shift when the light emitting parts are installed, and the predetermined pitch between the light emitting parts can be maintained as is even at the time of installation (in other words, the accuracy of the installation can be improved). .

Therefore, when an image is recorded on a recording material using this LED chip, there will be no periodic density fluctuations (unevenness) in the sub-scanning direction, and therefore the recorded image will be of high quality. Become.

On the other hand, in the method for manufacturing an LED chip of the present invention, the LED chip is manufactured by cutting an LED wafer and dividing it into a plurality of chips.

When dividing into a plurality of chips, one of the P region and N@ region of the single chip to be divided is completely cut away, and these regions are separated from each other and separated into a plurality of independent chips. . Therefore, a plurality of separate and independent PN junction surfaces are integrally formed in a single chip, and the completed LED chip has multiple depletion regions (light emitting parts) in a single chip. Be prepared.

In this case, the pitch between the plurality of depletion regions (light emitting parts) (in other words, the pitch between the bonding surfaces) is a predetermined pitch (the same pitch as the sub-scanning pitch) at the time of manufacturing the LED chip.
It can be formed accurately and accuracy is also improved. Also,
L with different pitches between multiple light emitting parts
The ED chips are the same, and products can be made uniform. Furthermore, there is no need to change the manufacturing process (guishing process) in which the LED wafer is cut and divided into a plurality of chips, so there is no deterioration in cost or productivity.

When recording an image on a recording material using the manufactured LED chip, the plurality of light emitting parts of this LED chip are arranged along the sub-scanning direction, and the light from the plurality of light emitting parts is directed in the main scanning and An image is recorded on the recording material by sub-scanning.

In this case, in the past, multiple independent light sources were each mounted independently, which made it difficult to accurately mount them at a predetermined pitch (the same pitch as the sub-scanning pitch), and this led to high costs. In the LED chip manufactured by the manufacturing method according to the present invention, the plurality of independent light emitting parts are formed accurately at a predetermined pitch (the same pitch as the sub-scanning pitch) at the time of manufacturing the LED chip.
When installing the D-chip, the pitch between the plurality of light emitting parts will not deviate from the sub-scanning pitch, and the predetermined pitch between the light emitting parts can be maintained as is even at the time of installation (in other words, the pitch between the light emitting parts can be maintained as it is at the time of installation) can improve accuracy).

Therefore, when an image is recorded on a recording material using this LED chip, there will be no periodic density fluctuations (unevenness) in the sub-scanning direction, and therefore the recorded image will be of high quality. Become.

[Example code] The present invention will be explained in detail below.

FIG. 4 shows an image recording device 10 to which an LED chip according to an embodiment of the present invention is applied.

The image recording device 10 has a magazine 14 housed in the machine base 12.
A heat-developable photosensitive material 16, which is a ferro-shaped image forming sheet, is accommodated. The heat-developable photosensitive material 16 is pulled out from its outer periphery, cut into a predetermined length by a cutter 18, and then wound around the outer periphery of a rotating drum 20 in the six directions of arrows.

Correspondingly, an exposure head 22 is arranged on the outer periphery of the rotating drum 20 so as to be movable in the axial direction of the rotating drum 20 (in the direction perpendicular to the plane of the paper in FIGS. 2 and 4: in the direction of arrow C in FIG. 3). .

The exposure head 22 exposes the photothermographic material 16 wound around the rotary drum 20 in a line shape (hereinafter referred to as main scanning) by rotating the rotary drum 20 at high speed in the direction of arrow A.
At the same time, the rotating drum 20 is repeatedly moved in the axial direction (hereinafter referred to as sub-scanning) to expose an image.

After exposure, the photothermographic material 16 is transferred by rotating the rotating drum 20 in reverse (
In the direction of arrow B), the rotating drum 20 is removed by the scraper 24.
After being peeled off from the film and being coated with an image-forming solvent and water in a water application section 26, it is sent to a thermal development transfer section 28 whose interior is a heating section.

The thermal development transfer section 28 is composed of a heating drum 34 and an endless pressure belt 36. A halogen lamp 38 is disposed inside the heating drum 34, and the outer peripheral surface of the heating drum 34 is heated to about 90°C.

The heat-developable photosensitive material 16 sent to the heat-developable transfer section 28 is conveyed while being held between the heating drum 34 and the endless pressure belt 36 over approximately 2/3 of the circumference of the heating drum 34, so that it is thermally developed. It has become.

On the other hand, a tray 30 disposed below the thermal development transfer section 28
Inside are a plurality of image receiving materials 3 cut to a predetermined length.
The heat-developable photosensitive material 1 is stored therein, and is taken out one by one by a supply roller 44 disposed on the side.
6 and is sent to the thermal development transfer section 28 in a superimposed state.

A peeling claw 48 is disposed on the side of the heat development transfer section 28 and is designed to peel off the heat development photosensitive material 16 and the image receiving material 32 sent out from the heat development transfer section 28 from the outer periphery of the heating drum 34. .

A separation part 50 is arranged below the separation claw 48,
The image receiving material 32 is separated from the photothermographic material 16, bent and conveyed.

The separated photothermographic material 16 is stored in a waste photosensitive material storage box 5.
9, the image-receiving material 32
After being dried by a heater 54, it is delivered onto a take-out tray 56 formed at the top of the machine base 12.

As shown in FIGS. 2 and 3, the exposure head 22 includes a cylindrical lens barrel 60 serving as its main body, and a condenser lens 61 is disposed at one end of the lens barrel 60. . On the other hand, a stem 62 is attached to the other end of the lens barrel 60.

The inner peripheral surface of the stem 62 is anti-reflection treated.
Further, an insulating substrate 64 is fixed to the end portion.

Conductive bases 66.68 are fixed to the inner surface (surface on the lens barrel 60 side) of the substrate 64, and each base 66.6
8 is connected to heat dissipation bases 70 and 72 which penetrate the substrate 64 and serve as electrodes exposed to the outside.

On one base 66 is an LED chip 7 made of NP junction.
4 and LED chips 76 are attached at predetermined intervals. Further, the other base 68 has an LE made of a PN junction.
A D chip 78 is attached.

Each LED chip is manufactured by cutting an LED wafer with a diamond blade or the like and dividing it into a plurality of chips.

In this case, when dividing into multiple chips (guising process), either one of the P region and N region of the single chip to be divided is completely cut away, and these regions are separated from each other and become independent. Separated into multiple parts. Therefore, a plurality of separate and independent PN junction surfaces are integrally formed within a single chip, and the completed LED chip is a single chip with multiple depletion regions. It has become.

For example, as shown in FIG. 1, a cutting groove 75 is formed in the center of the N region of the LED chip 74, thereby completely dividing the N region into two. That is, two junction surfaces between the P region and the N region are formed independently from each other (in other words, two mutually independent depletion regions S (light emitting surfaces) are formed), and therefore, this LED chip 74 A single chip is provided with two mutually independent light emitting sections 74A and 74B.

The pitch between these two light emitting parts 74A and 74B is formed to be the same as the sub-scanning pitch.

In this example, the width of each LED chip (the dimension of one side of the light emitting part) is 300μ, and the width of the cutting groove is 60μ.
The pitch between the two light emitting parts is therefore 360μ.

Each LED chip is attached to each base so that each light emitting part is along the sub-scanning direction.

Electrodes 80 are attached to the substrate 64 near each LED chip, and each LED chip is bonded with a wire 82. In addition, each electrode has a substrate 64.
A wire 84 passing through is connected, thereby applying a voltage to each LED chip.

Here, each LED chip emits light of a different wavelength. That is, the LED chip 74
(The light emitting sections 74A, 74B> emit infrared light that develops cyan (C) dye into the photothermographic material 16, and the LED
The chip 76 (light-emitting sections 76A, 76B) emits red light that causes the photothermographic material 16 to develop a magenta (M) dye, and the LED chip 78 (light-emitting sections 78A, 7
8B) is designed to emit yellow light that causes the photothermographic material 16 to develop a yellow (Y) dye.

Here, since the light emitting part of each LED chip is attached along the sub-scanning direction, by activating all the LED chips (light emitting parts), it is possible to perform main scanning exposure of two lines at the same time. There is.

A light shielding plate 86 is placed immediately in front of each LED chip. The light shielding plate 86 is subjected to anti-reflection treatment, and furthermore, an aperture 88A is provided at a position corresponding to each LED chip.
, 88B, 90A, 90B.

92A and 92B are formed. These apertures 88A, 88B, 90A, 90B, 92A, 92B are
They correspond to the LED chips 74Δ, 74BS LED chips 76A, 76B and LED chips 78A, 78B arranged in parallel, and are accurately formed at predetermined intervals by a method such as etching.

Therefore, the outer diameter of the light emitted forward from each LED chip is limited by the aperture arranged corresponding to the LED chip, so that flare is reduced and the light enters the condenser lens 61. ing.

Next, the operation of this embodiment will be explained.

When the photothermographic material 16 pulled out from the magazine 14 is cut by the cutter 18 and wound around the outer circumference of the rotating drum 20, the rotating drum 20 rotates at high speed (in the direction of arrow C in FIGS. 2 and 3). At the same time, the exposure head 22 moves in the axial direction of the rotary drum 20 (in the direction of arrow C in FIG. 3) (main scanning and sub-scanning are performed), and the image is exposed.

In this case, in the exposure head 22, each LED chip emits light of a different wavelength. That is, the LED chip 74 (light-emitting portions 74A, 74B) is connected to the heat-developable photosensitive material 16.
Infrared light that develops cyan (C) pigment is emitted into the L
The ED chip 76 (light-emitting parts 76A, 76B) emits red light that develops magenta (M) dye on the photothermographic material 16, and furthermore, the LED chip 78 (light-emitting parts 78A,
78B) emits yellow light that causes the photothermographic material 16 to develop a yellow (Y) dye.

The emitted light passes through an aperture 8 formed in a light shielding plate 86.
8A, 88B, 90A, 90B, 92A, and 92B limit the outer diameter of the light, thereby reducing flare, and the light enters the condenser lens 61. The incident light is condensed by a condensing lens 61 and formed into an image on the photothermographic material 16, where it is recorded as a latent image of a dot pattern. Furthermore, this three-color exposure is repeated in synchronization with the rotation of the rotating drum 200 times according to the image information, thereby recording an image.

Here, this image is exposed using all of the light emitting parts of two LED chips formed and attached along the sub-scanning direction.
Since two lines of main scanning exposure are performed simultaneously, the time required for image recording can be significantly shortened.

In addition, in this case, because the conventional exposure head had multiple independent light sources (LED chips) each mounted independently, each light source was arranged at a predetermined pitch (same pitch as the sub-scanning pitch).
It is not easy to accurately mount the device, and only a precision of a few hundred microns can be ensured. Moreover, this resulted in high costs.

On the other hand, in the exposure head 22, for example, a single LED
Two light emitting parts 7 formed independently of each other on the chip 74
4A and 74B are formed by cutting with a diamond blade etc. at the time of manufacturing this LED chip 74, and furthermore, since cutting and cutting with a diamond blade etc. can ensure accuracy of several tens of microns, these light emitting parts 74A, 74B are They can be formed accurately and with high precision at a predetermined pitch (the same pitch as the sub-scanning pitch).

Furthermore, even if this LED chip is mounted on a base so that each light emitting part is along the sub-scanning direction, the pitch between the two light emitting parts will not deviate, and even at the time of installation, the distance between the light emitting parts The predetermined pitch can be maintained as is, and the mounting accuracy can be greatly improved compared to the conventional method.

Therefore, when an image is recorded on the photothermographic material 16 using this LED chip, there will be no periodic density fluctuations (unevenness) in the sub-scanning direction, and therefore the recorded image will be High quality.

In addition, the pitch between the two light emitting parts of each LED chip is
Even if a plurality of different LED chips are manufactured, they will be the same, and products can be made uniform. Furthermore, there is no need to change the manufacturing process (guishing process) in which the LED wafer is cut and divided into a plurality of chips, so there is no deterioration in cost or productivity.

After exposure, the heat-developable photosensitive material 16 is passed through the scraper 24! ll
, lit, coated with water in the water coating section 26, and sent to the thermal development transfer section 28.

On the other hand, the image receiving material 32 in the tray 30 is taken out one by one by the supply roller 38 and sent to the thermal development transfer section 28 while being in close contact with the photosensitive material 16.

The heat-developable photosensitive material 16 and the image-receiving material 32 sent to the heat-developable transfer unit 28 remain in close contact with each other between the heating drum 34 and the endless pressure belt 36, which are heated to about 90° C. by the halogen lamp 38. approximately 2/3 of heating drum 34
The image is transferred to the image-receiving material 32 while being pinched and conveyed around the circumference and thermally developed.

After the transfer, the heat-developable photosensitive material 16 and the image-receiving material 32 are peeled off from the heating drum 34 by the peeling claw 48 and further separated! 850. The separated heat-developable photosensitive material 16 is sent to a waste photosensitive material storage box 59,
The image receiving material 32 is taken out to a takeout tray 56 via a heater 54 .

In the present embodiment, each LED chip has a configuration in which two mutually independent light emitting parts R (PN junction surface) are formed along the -axis, but the present invention is not limited to this. It may also be configured to be integrally formed. Even in this case, the pinch between the light emitting parts can be formed with high precision, and the pitch does not shift at the time of installation, and a high quality image can be obtained.

In addition, in this embodiment, the LED chips of all three colors are configured so that two mutually independent light emitting parts are integrally formed, but the present invention is not limited to this. The configuration may be such that two mutually independent light emitting parts are integrally formed.

Furthermore, in this example, three different color light sources (LED
Although the image recording apparatus 10 that obtains a color image using a chip) has been described, the present invention is not limited thereto, and can be applied to an image recording apparatus that obtains a monochromatic image using a single light source.

[Effect of the invention] As explained above, the present invention has the following effects.

In the LED chip according to claim (1), the mounting can be performed at a predetermined pitch (the same pitch as the sub-scanning pitch) by improving the accuracy of the position (pitch between light-emitting parts of the same color) without deteriorating cost or productivity. As a result, when an image is recorded, a high-quality image without periodic density fluctuations (unevenness) in the sub-scanning direction can be formed.

Further, in the method for manufacturing an LED chip according to claim (2), it is possible to accurately form a plurality of independent light emitting parts at a predetermined pitch (the same pitch as the sub-scanning pitch) in a single LLED chip. This also improves installation accuracy. Also,
LEs with different pitches between multiple light emitting parts
Since the D chips are the same, uniformity of products can be achieved.

Furthermore, there is no need to change the manufacturing process of cutting the LED wafer and dividing it into multiple chips, so there is no deterioration in cost or productivity.

Further, when an image is recorded using an LED chimbu manufactured by this method, a high-quality image without periodic density fluctuations (unevenness) in the sub-scanning direction can be formed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an LED chip according to an embodiment of the present invention;
FIG. 2 is a schematic sectional view of an exposure head using an LED chip, FIG. 3 is a schematic perspective view of the exposure head showing how the LED chip is mounted, and FIG. 4 is a schematic configuration diagram of an image recording apparatus. 10... Image recording device, 16... Photosensitive material, 20... Rotating drum, 22... Exposure head, 74... LED chip, ? 4A, 74B... Light emitting part, 76... LED chip, 76A, 76B... Light emitting part, 78... LED chip, 78A, 78B... Light emitting part. 4A 74: u:o odd l file 74A/74B2 house part

Claims (2)

[Claims] (1) Of the integrally formed P region and N region,
An LED chip in which one of the regions is continuous, the other region is separated into a plurality of independent and spaced apart regions, and has a plurality of independent PN junction surfaces that are spaced apart from each other. (2) A method for manufacturing an LED chip in which an LED wafer is cut and divided into a plurality of chips, and when dividing into the plurality of chips, either the P region or the N region of a single chip is selected. Fabrication of an LED chip characterized by completely cutting one region and separating this region into a plurality of separated and independent regions, thereby forming a plurality of separated and independent PN junction surfaces within a single chip. Method.