JPH0210879A - Light emitting diode array - Google Patents

Abstract

PURPOSE:To facilitate accurate alignment by so full-cut dicing the surface of an LED array having a light emitting unit as to reduce the area of the rear face by a dicing plate having an angled face. CONSTITUTION:After a light emitting unit 4 is formed on a whole wafer face, it is cut and separated by a dicing saw from the rear face 3. ln this case, a dicing plate 20 to be used has a face 21 so angled as to form a V shape on the outer periphery, and the rear face of the wafer is full-cut diced by the plate 20 to form the shape of the LED array side face 5. Thus, the length of the array 1 is short at the rear face 3 with respect to the front face 2. Thus, the array having no dicing mark on the side face can be composed, and accurately aligned at a predetermined light emitting unit pitch.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an optical writing optical printer head in a non-impact printer using an electrophotographic method [Prior art] Fig. 4 shows an optical writing head used in a conventional optical printer head. L was being
FIG. 5 is a perspective view showing the structure of an IuD array, and FIG.
FIG. 2 is a cross-sectional view of main parts showing the configuration of an ED array. Code 2 in the diagram
is the surface of the LED array, on which a plurality of light emitting parts 4 are arranged in a straight line. In the manufacturing process of the L]lCD array, after a large number of light emitting parts 4 are formed on the wafer, half-cut dicing grooves 11 with a depth of Td are formed from the main surface 2 side using a dicing tool. The portion is cut by cracking and separated into individual LED arrays. Due to this cracking, the dicing cut protrudes 1.
Two types of shapes, 2-1 and dicing cut recess 12-2, occur irregularly. In other words, the half-cut dicing grooves 11 are provided on the four sides around the LED array 1, and the appearance positions of the dicing cut convex 12-1 and the dicing cut concave 12-2 are not uniformly determined; and FIG. 5 only show one example.

[Problems to be Solved by the Invention] However, in an optical print head configured by aligning and fixing a plurality of LED arrays on a substrate with high precision alignment, it is difficult to use LED arrays cut from a wafer using a conventional dicing method. If this were the case, the LKD array chip dimensions would be disturbed by the dicing trace 12, resulting in a problem that it would be extremely difficult to perform highly accurate positioning.

In addition, since the light emitted from the light emitting part closest to the dicing historical site leaks from the dicing historical site, even if the leaked light is small, it exposes the photoreceptor, resulting in a problem in that printing quality is impaired. There is.

Therefore, the present invention aims to solve these problems.
The purpose is to obtain an LED array that can easily perform high-precision positioning and that does not impair printing quality due to leakage light from dicing historical sites.
An object of the present invention is to provide an optical printer head equipped with an ED array.

[Means for Solving the Problems] In order to solve the above problems, the present invention has a plurality of light emitting parts on the surface, and a plurality of light emitting parts are placed and fixed on a substrate to constitute an optical print head for optical writing. The LED array is characterized in that full-cut dicing is performed from the back surface side using a dicing blade having an angled surface so that the area of the back surface is smaller than the front surface having the light emitting part of the LED array.

[Function] According to the above configuration, full-cut dicing is performed from the back side of the LED array, so the area on the back side is smaller than the front side of the LED array, and there is no dicing history seen in conventional LED arrays. .

[Example] Therefore, details of the present invention will be explained below based on an example.

FIG. 1 is a perspective view showing the structure of an LED array according to the present invention, and FIG. 2 is a sectional view of a main part showing the structure of the LED array. Reference numeral 1 in the figure is an LED array, on the surface 2 of which light emitting parts 4 are arranged in a linear arrangement. This step is carried out all at once in the wafer state, and after the light emitting portion 4 is formed on the entire surface of the wafer, the wafer is cut and separated from the back surface 3 side using a dicing saw. At this time, as shown in FIG. 3, the dicing blade used has a surface 21 angled so that the outer periphery is V-shaped. The shape of the LED array side surface 5 is formed by cutting and dicing. As a result, the length of the LED array 1 on the back surface 3 becomes shorter than that on the front surface 2. In other words, I, T>LB
becomes.

Furthermore, the same applies to the width direction of the LED array with respect to the light emitting unit alignment direction. In this example,
External angle α of the angle between the side surface 5-1 of the LED array 1 and the back surface 3
(0), the front and back lengths Ha at the ends of the LICD array are calculated for the case where the height of the LED array is H = 500 μm, and a comparative experiment is performed to determine the front and back length G. It was Tsugamitsu who determined the valid value. When α≦80°, the angle of the dicing blade made it difficult to configure the surface, and when α≦60°, chipping occurred near the LED array surface. In this example, α=70° was set, but α=65 to 80°.
Further, since full-cut dicing is performed, the conventional LED ID array dicing trace shown in FIG. 6 does not occur. (α>, <b> in FIG. 6 shows the case where the conventional LED ID array is cracked after half-cut dicing from the above-mentioned surface 2 side,
CC') 9Cd) in FIG. 6 shows the case where cranking is performed after half-cut dicing from the back side 3, and (α) in FIG. 6 respectively.

(C) is the dicing historical site convex 12-1, and (b) in Figure 6
, (d) is the dicing historical recess 12-2. As shown in FIG. 6, the light emitted from the nearest light emitting section 4 leaks from the dicing historical site 12, but even if the leaked light is small, it exposes the photoreceptor, thereby impairing printing quality. Furthermore, while the conventional LED array surface length is Lo, the actual LED ID array length due to the die cutting cut 12-1 is LO + L (l, so multiple LED ID arrays are aligned in the light section alignment direction. In optical printer heads, it has been difficult to maintain a constant pitch P between adjacent LED arrays, which has caused deterioration in print quality.In this embodiment, a dicing blade 20 having an angled surface 21 is used. Using LEDID array surface 3
Since full-cut dicing is performed from the side, the I and ED arrays do not have the dicing historical site 12, and the LFjD
There is no leakage of light from the outer periphery of the array, and furthermore, it is possible to form an LED ID array with good printing quality, which allows for high-precision positioning in which the pitch P of the light emitting parts between adjacent LKD arrays is kept constant. In addition, in order to configure an optical print head with a desired print width, a plurality of LED ID arrays must be placed and fixed in a line using electrical adhesive 6, but at this time, in the conventional LKDID array configuration, the seventh As shown in (α) in the figure, the conductive adhesive 6 fills the gap between the I and KD arrays, and in some cases, as shown in FIG. This may cause the n-side electrode to be electrically short-circuited or the light-emitting part to be optically blocked, making the optical printer functionally inoperable and significantly hindering the assembly of the optical printer head. However, according to this example, the gap between the LED arrays becomes larger as shown in Ch) in FIG. 7, and the conductive adhesive 6
This also has the effect of preventing unnecessary filling between adjacent LBD arrays.

[Effects of the Invention] According to the present invention, it is possible to perform full-cut dicing from the back side using a dicing blade having an angled surface to form an LED ID array without any dicing traces on the side surface separated from the LED array. Keeping the pitch of the light emitting part constant and performing high-precision positioning, LI
Since the photoreceptor is not exposed to light leaking from the outer periphery of the D array, the LED ID array has extremely good printing quality. Furthermore, it is possible to prevent filling of conductive adhesive between adjacent LED arrays, and has the unique effect of improving the ease of assembling an optical printer head in which several LED ID arrays are aligned and fixed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of an LID array according to the present invention, and FIG. 2 is a side view of essential parts showing the structure of the LED ID array. FIG. 3 is a cross-sectional view of a dicing blade used for dicing the LFiD array. Figure 4 is a perspective view showing a conventional LED ID array structure;
The figure is a side view of essential parts showing the configuration of the LED ID array. FIGS. 6(α) to 6(d) are cross-sectional views showing examples of dicing history of conventional L/ED arrays. Figure 7(α)(b) is
FIG. 3 is a cross-sectional view showing how conductive adhesive is filled between LED arrays. FIGS. 8(α) and 8(b) are cross-sectional views showing the electrical short circuit between the p-n junctions and the light shielding of the light emitting part by the conductive adhesive. 1...LEDID array...LID array surface 3...LEDID array surface 4...Light emitting part 5...LEDID array surface 11... ... Dicing groove 12 ... Dicing historical site 20 ... Dicing blade diagram Diagram ... Angled surface

Claims (1)

[Claims] In a light emitting diode array (hereinafter referred to as an LED array) which has a plurality of light emitting parts on its surface and which is mounted and fixed on a substrate to constitute an optical print head for optical writing, 1. A light emitting diode array characterized in that full-cut dicing is performed from the back surface side using a dicing blade having a curved surface so that the area of the back surface is smaller than the front surface having a light emitting part of the LED array.