JP5511181B2 - Manufacturing method of optical element head - Google Patents

Description

  The present invention relates to a method for manufacturing an optical element head in which a plurality of light receiving elements or light emitting elements are arranged in a line.

  A print head used as exposure means for an electrophotographic printer or the like has, for example, a structure in which a plurality of LED arrays are arranged on an upper surface of a printed board on which a predetermined pattern of wiring conductors are attached. For example, in a print head, a predetermined power is applied to each LED element of the LED array based on a print signal from the outside, and the LED elements are selectively emitted individually, and the emitted light is externally transmitted through a lens. Then, a predetermined latent image is formed on the surface of the photosensitive drum.

Conventionally, when an LED array is arranged on the upper surface of a printed board, an adhesive is arranged on the upper surface of the printed board as described in, for example, Patent Document 1 below, and the LED array is pressed against the adhesive. The LED array was bonded to the upper surface of the printed circuit board by heating and curing the adhesive. Conventionally, a sufficient amount of adhesive in the gap between the upper surface of the printed circuit board and the LED array in order to bond the LED array to the upper surface of the printed circuit board relatively firmly and with relatively high positional accuracy. The LED array was bonded to the side of the printed circuit board while being pressed.
Japanese Patent Laid-Open No. 9-095010

  In recent years, in accordance with an increase in image quality required for a print head, in order to make the interval between the arrangement positions of a plurality of LED elements relatively small, it is required to make the interval between adjacent LED arrays relatively small. When the interval between adjacent LED arrays is made relatively small, naturally the gap between the end faces of each LED array becomes narrow. In this case, there is a problem that the adhesive disposed on the upper surface of the printed circuit board wets the gap between the end surfaces and easily reaches the LED elements and wire bonding pads provided in the LED array. If the adhesive reaches the LED element, the LED element's light emission may be blocked by the adhesive or the element may be damaged. If the adhesive reaches the wire bonding pad, bonding failure may occur. May occur, leading to a failure of the print head itself. The present invention aims to solve this problem.

In the method of manufacturing an optical element head according to the present invention, a base having thermal polymerization property and a photopolymerization initiator that proceeds with a polymerization reaction of the base by receiving light in a specific wavelength range are included on the upper surface of the substrate. A step of arranging a plurality of optical element arrays through a gap in a specific direction via a bonding agent, and irradiating the bonding agent in the gap with light in the specific wavelength range from the upper surface side of the optical element array A step of photopolymerizing at least an upper end surface of the bonding agent in the gap; and after irradiating the bonding agent in the gap with light, the entire bonding agent is heated to polymerize the entire bonding agent. And a step of performing.

  According to the method for manufacturing an optical element head of the present invention, the bonding agent can reach the upper surface of the optical element array while bonding the substrate and the optical element array relatively firmly with the bonding agent with less labor and cost. A suppressed optical element head can be manufactured.

  1A and 1B are schematic views showing the configuration of an optical element head X according to an embodiment of the present invention, where FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line Ib-Ib. The optical element head X includes an optical element array 10, a substrate 20, and a bonding member 30.

  The optical element array 10 includes an optical element 11 and a base substrate 12, and further includes a wire bonding pad 13 in this embodiment. In the present embodiment, the plurality of optical element arrays 10 are arranged along the arrow AB direction. The optical element array 10 according to the present embodiment has a rectangular parallelepiped shape including an upper surface 10a (an upper surface of the base substrate 12), a lower surface 10b (a lower surface of the base substrate 12), and an end surface 10c (an end surface of the base substrate 12). However, it is not limited to such a shape. The optical element 11 irradiates light toward the irradiation target, and in the present embodiment, a plurality of optical elements 11 are arranged along the arrow AB direction. Examples of the light source element 11 include an LED element and an EL element. Among these, an LED element is preferable from the viewpoint of reducing power consumption and noise. The base substrate 12 has a plurality of optical elements 11 mounted on the upper surface thereof. The wire bonding pad 13 transmits a printing signal to the optical element 11 and is electrically connected to the optical element 11. In the present embodiment, the wire bonding pad 13 is mounted on the upper surface of the base substrate 12.

  The substrate 20 is for mounting the optical element array 10. The constituent material of the substrate 20 may be any material, but is preferably made of an electrically insulating resin such as a glass epoxy resin from the viewpoint of insulation. In the present embodiment, the optical element array 10 is disposed on the upper surface 20 a of the substrate 20. In the present embodiment, the substrate 20 has a rectangular parallelepiped shape, but is not limited to such a shape.

The joining member 30 joins the optical element arrays 10 adjacent to each other and the optical element array 10 and the substrate 20. In the present embodiment, the bonding member 30 is disposed in the first gap K1 between the adjacent optical element arrays 10 and the second gap K2 between the lower surface 10b of the optical element array 10 and the upper surface 20a of the substrate 20. The exposure unit 31 including the upper end surface 31a of the bonding member 30 in the first gap K1 includes a photopolymerization unit. In the present embodiment, the upper end surface 31 a is located below (in the direction of arrow D) the upper surface 10 a of the optical element array 10. Further, the protruding portion 32 a from the optical element array on the upper surface 20 a of the substrate 20 includes a thermal polymerization portion. Here, the thermal polymerization refers to polymerization by heating, and the thermal polymerization portion refers to a portion that is mainly thermally polymerized. Photopolymerization refers to polymerization by receiving a specific wavelength, and the photopolymerization part refers mainly to a photopolymerized part. In photopolymerization, radical species are generated from a photopolymerization initiator by irradiation with light, and the generated radical species are successively polymerized with a monomer (monomer) or oligomer (low polymer) to grow. Through the process of becoming a merger. Therefore, the photopolymerization part of the exposure part 31 of the joining member 30 in the first gap K1 contains more elements that constitute radical species in the polymer than other parts. The bonding member 30 before polymerization is configured by adding, for example, a photopolymerization initiator that receives light in a specific wavelength range and advances a polymerization reaction of the base to a base having thermal polymerization properties. Examples of the base having thermal polymerizability include urethane acrylates, epoxy acrylates, ester acrylates, acrylate monomers and oligomers. Examples of the photopolymerization initiator include diethoxyacetophenone, isopropyl benzoin ether, and benzophenone.

  The optical element head X according to the present embodiment enhances the bonding between the optical element array 10 and the substrate 20 and increases the density of the optical element array, and reduces the function of the optical element array 10 caused by the bonding member 30. It is suitable for suppressing the above.

  A method for manufacturing the optical element head X according to the embodiment of the present invention will be described. FIG. 2 is a flowchart of the manufacturing method of the optical element head X.

  First, an optical element array 10 in which a plurality of optical elements 11 arranged along a specific direction are arranged on the upper surface 10a is manufactured. Specifically, for example, a plurality of semiconductor layers are stacked on the surface of the base substrate 12 made of, for example, a semiconductor substrate by using, for example, the MOCVD method, and then an etching process, an electrode formation process, and the like are performed (step S101). Thereafter, the base substrate 12 is diced, for example, and a plurality of optical element arrays 10 are cut out. At this time, by adjusting the angle of the dicing blade in the dicing process, as shown in FIG. 3A, the end surface 10c of the optical element array 10 is placed on the upper surface 10a of the optical element array 10 (the upper surface of the base substrate 12). It is good also as the slope which approaches the center position (center position of arrow AB direction) of the light source element array 10 as it approaches the lower surface 10b (lower surface of the base substrate 12) side of the optical element array 10 from the side. According to such a configuration, wetting of the bonding agent 30 described later can be reduced. Further, as shown in FIG. 3B, a groove M1 may be provided on the lower surface 10b of the optical element array 10. According to such a structure, the area | region which spreads along a specific direction is suppressed because the below-mentioned bonding agent 30 permeate | transmits into a groove part partially.

  Next, as shown in FIG. 4A, a substrate 20 made of glass epoxy resin or the like is prepared, and a bonding agent 30 having fluidity is applied to a predetermined position on the upper surface 20a of the substrate 20 (step S102). Here, the predetermined position is a partial region corresponding to a portion where the optical element array 10 is arranged. Further, as shown in FIGS. 4B and 4C, a groove M2 may be provided in a portion corresponding to the lower surface 10b of the optical element array 10 on the upper surface 20a of the substrate 20. According to such a structure, the area | region which expands along a specific direction is suppressed because the part which the bonding agent 30 expanded along the specific direction permeates into the groove part M2.

  Next, a plurality of optical element arrays 10 are arranged side by side along a specific direction on the bonding agent 30 applied to the upper surface 20a of the substrate 20 (step S103). At this time, the gap between the end faces 10c in the plurality of optical element arrays 10 is set to a predetermined size. In addition, when the optical element array 10 is arranged, as shown in FIG. 5A, a part of the bonding agent 30 is adjacent to the gap between the lower surface 10b of the optical element array 10 and the upper surface 20a of the substrate 20. It penetrates into the gap between 10 and wets the gap by capillary action.

  Next, as shown in FIG. 5B, a part of the bonding agent 30 is irradiated with light (light in a specific wavelength range) to the gap between the adjacent optical element arrays 10 and enters the gap by capillary action. Is cured (polymerized) (step S104). At this time, light is irradiated from the upper surface 10a side (arrow C direction side) of the optical element array 10 using a known light irradiation source. The vicinity of the upper end surface of the bonding agent 30 maintained in a portion relatively close to the upper surface 10a of the optical element array 10 is photopolymerized and cured by this light irradiation. Thereby, the end surfaces 10c of the plurality of optical element arrays 10 are joined by the photopolymerization portion provided in each gap. In this state, the bonding agent 30 includes the exposed portion 31 and the non-exposed portion 32. The exposed portion 31 is a portion that has been sufficiently irradiated with light and refers to a portion that includes a photopolymerization portion, and the non-exposed portion 32 refers to a portion that is weakly irradiated with light.

  Next, as illustrated in FIG. 6B, the exposure unit 31 and the non-exposure unit are pressed while pressing the optical element array 10 against the substrate 20 in a state where the adjacent optical element arrays 10 are bonded via the exposure unit 31. 32 is heated to cure (polymerize) the entire bonding agent 30 (step S105). By pressing the optical element array 10 against the substrate 20, the non-exposure portions 30 are distributed with a relatively high uniformity in the gap between the lower surface 10 c of the optical element array element 10 and the upper surface 20 a of the substrate 20. Therefore, by heating in this state, the substrate 20 and the optical element array 10 are bonded with a relatively high strength. Further, since the position of the optical element array 10 is fixed by the pressing, a minute position variation due to the flow of the non-exposure portion 32 due to heating is suppressed, and the position of the upper surface 10a of the light source element array 10 and the position of the optical element 11 is compared. Set with high accuracy. At this time, the exposure part 31 in the gap between the adjacent optical element arrays 10 blocks the non-exposure part 32 that wets the gap and suppresses the progression of the non-exposure part 32 toward the upper surface 10a of the optical element array 10. . Therefore, even when heated while pressing, the non-exposed portion 32 does not reach the upper surface 10a of the optical element array 10, and the optical element array 10 and the substrate 20 are bonded with high accuracy. Further, when the optical element array 10 is pressed against the substrate 20, as shown in FIG. 6A, a part 32 a of the non-exposure portion 32 flows out from a portion corresponding to the optical element array 30 on the upper surface 20 a of the substrate 20. .

  The optical element head X of the present embodiment may be manufactured as described above. The bonding agent 30 is applied to the upper surface 20a of the substrate 20, and the optical element array 10 is not limited to be disposed on the applied bonding agent 30. For example, the bonding agent 30 is applied to the lower surface 10b of the optical element array 10. The optical element array 10 may be applied and disposed on the upper surface 20 a of the substrate 20 via the bonding agent 30.

  The manufacturing method of the optical element head X according to this embodiment is manufactured through the above-described steps. Therefore, an optical element head is manufactured in which the distance between the optical element arrays 10 is narrowed, and even when a large amount of the bonding agent 30 is applied, the bonding agent 30 is prevented from getting wet on the upper surface of the optical element array. can do.

  Therefore, the optical element head X aims to strengthen the bonding between the optical element array 10 and the substrate 20 and increase the density of the optical element array, and suppress the deterioration of the function of the optical element array 10 caused by the bonding member 30. It is suitable in the above.

  FIG. 7 is a cross-sectional view illustrating a schematic configuration of a printer Y including the optical element head X according to the present invention. The printer Y includes an optical element head X, a photosensitive drum 40, a developing device 50, a transfer belt 60, a registration roller pair 70, and a fixing roller pair 80.

  The photosensitive drum 40 can form a latent image with light from the optical element head X, and can print on a recording sheet with the formed latent image. In this embodiment, the photosensitive drum 40 is disposed below the optical element head X (in the direction of arrow C) so as to be separated by a predetermined distance. In the present embodiment, a plurality of photosensitive drums 40 are arranged in the direction of arrow EF. The photosensitive drum 40 has a structure in which a photoconductive layer made of an inorganic semiconductor such as amorphous silicon or an organic semiconductor is deposited on the outer surface of a cylindrical base made of aluminum metal or the like.

  The developing device 50 allows the latent image formed on the photosensitive drum 40 to be visible as a toner image with toner. In the present embodiment, the developing device 50 is provided around each photosensitive drum 40.

  The transfer belt 60 plays a role of transferring the toner image on the photosensitive drum 40 onto a recording sheet, and is disposed below the photosensitive drum 40 (in the direction of arrow C) in the present embodiment.

  The registration roller pair 70 plays a role in conveying the recording paper onto the transfer belt 60 and is arranged on the arrow F direction side in this embodiment.

  The fixing roller pair 80 plays a role of receiving the transferred recording paper from the transfer belt 60 and performing a fixing process, and is arranged on the arrow E direction side in the present embodiment.

  In the printer Y, a plurality of optical element heads X arranged in the direction of the arrow EF form latent images on the corresponding photosensitive drums 40, and the latent images become toner images through a development process. Is copied onto a recording sheet fed from the registration roller pair 70, and the copied recording sheet is sent to the fixing roller pair 80, and a predetermined image is recorded by fixing the toner image on the recording sheet.

  The printer Y includes an optical element head X. Therefore, since the wetting of the bonding member 30 is suppressed in the gap between the optical element arrays 10, a good latent image can be formed even on the portion of the photosensitive drum corresponding to the gap. Therefore, the printer Y can provide a high-quality image.

  The specific embodiment of the present invention has been described above, but the present invention is not limited to this.

It is the schematic showing the structure of the optical element head which concerns on embodiment of this invention, (a) is a top view, (b) is sectional drawing along Ib-Ib. It is a flowchart of the manufacturing method of the optical element head shown in FIG. It is sectional drawing which shows the modification of the optical element array in the optical element head shown in FIG. (A) is the schematic explaining the manufacturing method of the optical element head shown in FIG. 1, and is sectional drawing which shows the process of apply | coating a bonding agent. (B) is sectional drawing which shows the modification of the board | substrate in the optical element head shown in FIG. (C) is a top view of the board | substrate of (b). It is the schematic explaining the manufacturing method of the optical element head shown in FIG. 1, (a) is sectional drawing which shows the process of arrange | positioning an optical element array to a board | substrate, (b) is the process of irradiating light to a bonding agent. FIG. It is the schematic explaining the manufacturing method of the optical element head shown in FIG. 1, (a) is a top view which shows the process of heating a bonding agent, (b) is IVb-IVb which shows the process of heating a bonding agent. It is sectional drawing along a line. It is sectional drawing showing schematic structure of a printer provided with the optical element head shown in FIG.

Explanation of symbols

X optical element head Y printer 10 optical element array 11 optical element 12 base substrate 20 substrate 30 bonding member, bonding agent 40 photosensitive drum 50 developing device 60 transfer belt 70 registration roller pair 80 fixing belt

Claims (7)

A plurality of optical element arrays on the upper surface of the substrate via a bonding agent comprising a base having thermal polymerizability and a photopolymerization initiator that receives light in a specific wavelength range and advances a polymerization reaction of the base. Arranging them through a gap in a specific direction;
Photopolymerizing at least the upper end surface of the bonding agent in the gap by irradiating the bonding agent in the gap with light in the specific wavelength range from the upper surface side of the optical element array;
And a step of thermally polymerizing the entire bonding agent by irradiating the bonding agent in the gap with light and then heating the entire bonding agent . 2. The method of manufacturing an optical element head according to claim 1, wherein, in the step of thermally polymerizing the bonding agent, the optical element array is pressed against the upper surface of the substrate. 3. The optical according to claim 1, wherein, in the step of thermally polymerizing the bonding agent, an upper end surface of the bonding agent in the gap is positioned below an upper surface of the optical element array. Manufacturing method of element head. 4. The method of manufacturing an optical element head according to claim 1, wherein a concave groove is provided in a portion corresponding to the lower surface of the optical element array on the upper surface of the substrate. 5. 5. The method of manufacturing an optical element head according to claim 1, wherein a concave groove is provided on a lower surface of the optical element array. 6. The method of manufacturing an optical element head according to claim 4, wherein the concave groove is continuous in a direction orthogonal to the specific direction over at least a range corresponding to the optical element array. The optical device according to any one of claims 1 to 6, wherein an end surface of the optical element array includes a slope region that approaches a center position in the specific direction of the optical element array as approaching from the upper side to the lower side. Manufacturing method of element head.