JPH067947U - LED print head - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a reliable connection between the driver IC and the substrate electrode even when the accumulated error between the input electrode of the driver IC and the substrate electrode becomes large. [Structure] The LED array chip 14 and the substrate 11 are bridged by a driver IC 18, and
In an LED print head in which the ED electrode 15 and the output electrode 19 of the driver IC, and the input electrode 20 of the driver IC and the substrate electrode 13 are opposed to each other and are directly connected,
The D electrode 15 and the output electrode 19 of the driver IC are formed parallel to the arrangement direction of the LED array chip 14, and the substrate electrode 13 is formed.
Are formed in a direction parallel to the arrangement direction of the LED array chips 14, and the input electrodes 20 of the driver IC are arranged in a direction perpendicular to the arrangement direction of the LED array chips 14.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is an LED print head in which an LED array chip and a substrate are bridged by a driver IC, and an electrode of the LED array chip and an output electrode of the driver IC face each other, and an input electrode of the driver IC and a substrate electrode face each other and are directly connected. It is about.

[0002]

[Prior art]

 Conventional techniques in this field include those disclosed in Japanese Utility Model Laid-Open No. 62-167645 and Japanese Patent Application Laid-Open No. 2-281976, which use conventional wire bonding in order to directly connect the facing electrodes. Compared to the LED head using, the large number of wires is unnecessary and the number of steps can be reduced.

FIG. 2 is a configuration diagram of such a conventional LED print head. As shown in this figure, two surfaces having different heights, that is, a low surface A and a high surface B are formed on the substrate 11. The LED array common electrode 12 is formed on the lower surface A, while the substrate electrode 21 is formed on the higher surface B of the substrate 11. Therefore, a conductive adhesive 17 is used on the LED array common electrode 12 so that the LED electrode 15 formed on the upper surface of the LED array chip 14 and the substrate electrode 21 are flush with each other. 14 is mounted.

Further, the substrate 11 and the LED array chip 14 are arranged so as to be bridged by the driver IC 18, and the facing LED electrode 15 and the output electrode 19 of the driver IC, the substrate electrode 21 and the input electrode 22 of the driver IC are respectively faced. The LED print head is constructed by connecting directly. Reference numeral 16 is a light emitting unit.

[0005]

[Problems to be solved by the device]

 However, in the conventional LED print head described above, there is no component that allows positional displacement between the LED array chip 14, the driver IC 18, and the substrate 11. Therefore, the LED array chip 14 and the driver IC 18 and the driver IC 18 and the substrate 11 have the disadvantage that the alignment accuracy must be extremely high.

However, in the chip-mounted device, a positional deviation occurs with respect to the position set by the accuracy of the operation of the device, the alignment accuracy, and the accuracy due to the structure of the device. With the current device, this positional deviation cannot be made zero. Further, the conventional substrate electrode 21 is formed in the direction perpendicular to the LED array chip 14, and the input electrode 22 of the driver IC 18 is arranged in the direction parallel to the LED.

Therefore, assuming a head of 300 dpi and A4 size using an LED array of 128 dots / chip, 20 LED array chips are required. On the other hand, the driver IC 18 has an output electrode 19 (80 μm pitch) corresponding to each LED array chip and an input electrode 22 (200 μm pitch) corresponding to the substrate electrode 21, and the same number of 20 as the LED array chip 14 is provided. is necessary. When mounting the driver IC 18, the driver IC 18 having a small connection pitch and the LED array chip 14 are considered important, but the driver IC 18 and the substrate electrode 21 must be surely connected.

Therefore, when the positional displacement amount of the LED array chip 14 that causes the largest positional displacement is predicted, the column direction of the LED array chips 14 is set to the X direction, the direction perpendicular to the column is set to the Y direction, and the position of the nth chip is set. When the displacement is represented by σnx or σny, the first chip is mounted at a position determined by the positional displacement accuracy of the chip mounting device, and the positional displacement with respect to the set position is represented by σ1x and σ1y.

In the case of the LED print head, since the next LED array chip is mounted on the basis of the LED array chip mounted in front so that adjacent LED array chips do not hit each other, the LED array chip mounted on the substrate has n The position of the th LED array chip has a small value of σny in the Y direction, while the X direction is a cumulative position shift from the 1st chip to the nth chip (for example, n = 20). A displacement of the value indicated by Σ _n-1 ²⁰ σnx occurs.

The maximum value at this time is n times the positional deviation tolerance in the X direction. Therefore, even if the alignment accuracy at the connection points of the LED array chips is 10 μm off the set value determined by the pitch of the light emitting parts, a maximum of 200 μm misalignment is accumulated on the final LED array chip. Will end up. As a result, the connection area between the input electrode 22 and the substrate electrode 21 of the driver IC becomes small, some terminals cannot be connected at all, and in the worst case, different electrodes are connected and the driver IC 18 is broken. was there.

As described above, according to the present invention, when the LED array chips are arranged in order from the first LED array chip and the final LED array chip is arranged, a large positional deviation due to an accumulated error occurs. It is an object of the present invention to eliminate the problem of poor connection between electrodes and substrate electrodes, and to provide an LED printhead in which good connection between the driver IC and substrate electrodes can be obtained even when the cumulative error increases. To do.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention bridges an LED array chip and a substrate with a driver IC to form an LED electrode of the LED array chip and an output electrode of the driver IC, and an input electrode and a substrate electrode of the driver IC, respectively. In an LED print head which is faced and directly connected, the LED electrodes and the output electrodes of the driver IC are arranged in parallel with the arrangement direction of the LED array chips, and the substrate electrodes are formed in the parallel direction with the arrangement direction of the LED array chips. In addition, the input electrodes of the driver IC are arranged in the direction perpendicular to the arrangement direction of the LED array chips.

[0013]

[Action]

 According to the present invention, as described above, the LED electrode and the output electrode of the driver IC are formed parallel to the arrangement direction of the LED array chip, and the substrate electrode is formed parallel to the arrangement direction of the LED array chip. The input electrodes of the driver IC are arranged in a direction perpendicular to the arrangement direction of the LED array chips.

Therefore, the LED array chip and the substrate are bridged by the driver IC, the electrode of the LED array chip and the output electrode of the driver IC, and the input electrode of the driver IC and the substrate electrode are faced to each other and are directly connected. Even in the case of LED print heads with a small degree, the positional deviation of the final chip that occurs when the LED array chips are mounted sequentially from the edge can be tolerated, and the input electrode of the driver IC can be reliably and satisfactorily connected to the substrate electrode. be able to.

[0015]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of an LED print head showing an embodiment of the present invention. As shown in this figure, the substrate 11 is formed with two surfaces A and B having different heights. The LED array common electrode 12 is formed on the lower surface A, and the substrate electrode 13 is formed on the higher surface B in a direction parallel to the arrangement direction of the LED array chips 14. On the LED array common electrode 12 of the substrate 11, the LED array chips are mounted in order from the first LED array chip so that the LED array chips 14 are arranged in a row using the conductive adhesive 17 so that the light emitting portions 16 are arranged in a row. To do.

Further, the input electrode 20 of the driver IC is arranged in a direction perpendicular to the arrangement direction of the LED array chips 14 so that it can be connected to the substrate electrode 13. That is, the substrate electrodes 13a, 13b ... Are formed so that the substrate electrodes 13 are parallel to the arrangement direction of the LED array chips 14, and the input electrodes 20 of the driver IC are connected to the LED electrodes 15 of the LED array chips 14. The output electrodes 19 of the driver IC are arranged on both sides of the driver IC 18 so as to be orthogonal to the arrangement direction of the output electrodes 19. That is, two rows of the input electrodes 20 _a1 , 20 _a2 , ... 20 _an and 20 _b1 , 20 _b2, ... 20 _bn of the driver IC are formed. For example, the substrate electrode 13 a and the input electrode 20 of the driver IC are formed. _a1 is connected, the input electrode 20 _b1 of the substrate electrode 13b and the driver IC are connected.

The mounting positional relationship of the LED array chip will be described below. Here, when the arrangement direction of the LED array chips is the X direction, the direction perpendicular to the row is the Y direction, and the positional deviation of the nth chip is represented by σnx or σny, the first chip indicates the positional deviation accuracy of the chip mounting device. It is mounted at a fixed position, and the positional deviation with respect to the set position is represented by σ1x and σ1y. As described above, in the case of the LED print head, the next LED array chip is mounted based on the previously mounted LED array chip so that adjacent LED array chips do not collide with each other. On the other hand, the position of the n-th LED array chip is as small as σny in the Y direction, while in the X direction from the 1st LED array chip to the n-th (eg n = 20) LED array chip. The positional deviation of the value indicated by Σ _{n = 1} ²⁰ σnx, which is the accumulation of the positional deviation of, occurs.

The maximum value at this time is n times the positional deviation tolerance in the X direction. When manufacturing a 300 dpi, A4 size head using the same 128 dot / chip LED array chip as described above, since 20 LED array chips are used, the positional deviation tolerance in the X and Y directions is 10 μm. However, the final LED array chip has a maximum displacement of 200 μm.

Next, the driver IC 18 is mounted so as to correspond to each electrode. When the LED print head configured as described above is used, the output electrode 19 of the driver IC and the LED electrode 15 having a fine connection pitch (80 μm pitch) are simply aligned with each other, and the input electrode 20 of the driver IC and the substrate are simply aligned. The electrode 13 can be reliably connected. That is, the deviation in the Y direction is only 10 μm, and there is no problem in connection between the input electrode 20 of the driver IC and the substrate electrode 13.

Also regarding the displacement in the X direction, since the substrate electrode 13 is arranged in the direction parallel to the arrangement direction of the LED array chips 14, that is, in the X direction, connection is possible even if there is a positional deviation of 200 μm. It doesn't matter at all. Further, the driver IC 18, the substrate 11 and the LED array chip 14 can be connected by an anisotropic conductive resin or a connection using a conductive resin.

In the above-described embodiment, the substrate electrode 13 is illustrated as being parallel to the arrangement direction of the LED array chips 14 and not interrupted in the middle, but the portion connected to the input electrode 20 of the driver IC is The object of the present invention can be achieved as long as it is parallel to the array direction of the LED array chips 14, and accordingly, the substrate electrode 13 can be modified such as cut or bent as appropriate based on this gist.

Further, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0023]

[Effect of device]

 As described above in detail, according to the present invention, the LED electrodes and the output electrodes of the driver IC are formed in parallel with the arrangement direction of the LED array chips, and the substrate electrodes are formed in the parallel direction with the arrangement direction of the LED array chips. In addition, since the input electrodes of the driver IC are arranged in the direction perpendicular to the arrangement direction of the LED array chip, the LED array chip and the substrate are bridged by the driver IC, and the electrode of the LED array chip and the output electrode of the driver IC are arranged. Also, even in the LED print head where the input electrode of the driver IC and the substrate electrode are faced to each other and are directly connected and the dimensional tolerance is small, the positional deviation of the final chip that occurs when the LED array chip is mounted sequentially from the end is allowed. However, the input electrode of the driver IC can be reliably and satisfactorily connected to the substrate electrode.

This makes it possible to easily manufacture a highly reliable LED print head with a small number of manufacturing steps.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an LED print head showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional LED print head.

[Explanation of symbols]

 11 substrate 12 LED array common electrode 13 substrate electrode 14 LED array chip 15 LED electrode 16 light emitting portion 17 conductive adhesive 18 driver IC 19 output electrode of driver IC 20 input electrode of driver IC

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location H04N 1/036 A 9070-5C (72) Creator Takehiko Makida 1-7 Toranomon, Minato-ku, Tokyo No. 12 Oki Electric Industry Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. An LED array chip and a substrate are driver ICs.
In the LED print head in which the LED electrode of the LED array chip and the output electrode of the driver IC and the input electrode of the driver IC and the substrate electrode are faced to each other and directly connected, the LED electrode and the output electrode of the driver IC Are arranged in parallel to the arrangement direction of the LED array chips, the substrate electrodes are formed in a direction parallel to the arrangement direction of the LED array chips, and the input electrodes of the driver IC are arranged in a direction perpendicular to the arrangement direction of the LED array chips. An LED print head characterized by being arranged.