JPH08130604A - Image equipment - Google Patents

Abstract

PURPOSE: To decrease the width of the equipment and to eliminate the need for alignment of a mirror by integrating the mirror of the image equipment and to use a lens with a long focal distance by increasing the length of an optical path. CONSTITUTION: A 2-layer wiring is applied to a transparent board 4 by using a via-sheet and an LED array 24 is connected to the board 4 by flip-chip. An end face of the board 4 is cut obliquely and a mirror 6 made of an aluminum vapor-deposit film is provided to reflect a light from the array 24 onto the mirror 6 and the reflected image is formed by a lens array 60. Since the two- layer wiring is provided onto a photosensing sheet of the via-sheet, soda-lime glass is enough for the transparent board 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image device such as an LED head, a plasma head and an image sensor.

[0002]

2. Description of the Related Art It has been proposed to provide a mirror in the optical path of an image device and bend the optical path by 90 degrees, for example. This has two meanings, and one is to use a lens having a long optical path and a long focal length. That is, if the optical path is lengthened and the focal length of the lens is lengthened, even if the optical path length between the light emitting / receiving array and the lens or the optical path length between the lens and the photoconductor or the document surface is changed, the influence on the imaging performance is reduced. . Therefore, even if there is some error, the effect on the image will be small,
It is possible to reduce the demand for the assembly accuracy of the image device. Another meaning is to reduce the front width of the image device. When the light emitting / receiving array is mounted on the substrate and the lens is arranged without using the mirror, the front width (width) of the image device is determined by the width of the substrate. And, for example, for a small facsimile or a small printer, it is important to reduce the front width of the image device.

However, when the image device is provided with a mirror, the positioning of the mirror is important. For example, if the angle of the mirror is improper, an image is not formed at a predetermined position, and if the distance between the mirror and the lens or the light emitting / receiving array is incorrect, the focusing performance deteriorates. Therefore, if a mirror is provided, a new problem of positioning the mirror arises.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to 1) integrate a mirror and a substrate, make positioning of the mirror unnecessary, and make angle adjustment of the mirror unnecessary (claims 1 and 2). The front width of the lens is reduced and a lens having a long focal length can be used to improve the imaging performance (claim 1). 3) The contamination of the multilayer wiring from the transparent substrate is prevented so that it can be used even on an inexpensive substrate (claims 2 and 3). 4) Multilayer wiring can be formed without a vacuum process to increase productivity (claim 2). 5) It is easy to realize complicated wiring for the light emitting / receiving array (claims 2 and 4). 6) It facilitates the formation of the mirror (claim 5).

[0005]

According to the present invention, in an image device in which wiring is provided on a transparent substrate and a light emitting / receiving array is flip-chip connected to the wiring, the end surface of the transparent substrate is formed obliquely and a mirror is formed on the end surface. Is provided (Claim 1). It is preferable that the end surface of the substrate is inclined by cutting, for example, and the angle is 45 degrees from the main surface of the substrate. Preferably, a resin film is provided on the transparent substrate, a first-layer wiring is provided on the resin film, and a second wiring is provided on the first-layer wiring.
The wiring of the second layer is provided via the resin film, and the wiring of the first layer and the wiring of the second layer are connected via the through hole provided in the second resin film (claim 2). Then, for example, soda glass is used for the transparent substrate (claim 3). Also preferably,
The light emitting / receiving array is an LED array, a large number of the LED arrays are arranged, and the second layer wiring is composed of a large number of U-shaped data buses provided along both sides of a column of the LED array. The wiring is provided below the U-shaped data bus, and the U-shaped data bus is connected to the first layer wiring by the through hole (claim 4). The mirror may be, for example, an aluminum tape adhered to the end surface of the transparent substrate, but preferably the mirror is a metal film formed on the end surface of the transparent substrate (claim 5). In this way, the mirror can be easily formed.

[0006]

According to the present invention, the light path of the light emitting / receiving array flip-chip connected to the transparent substrate passes through the transparent substrate and is bent by, for example, 90 degrees by the mirror. This is possible because a transparent substrate is used and flip-chip connection is performed. Since the optical path is bent by, for example, 90 degrees with the mirror, the front width of the image device is determined by the thickness rather than the width of the substrate.
The front width of the imaging device is reduced. When a mirror is used, the optical path length can be extended and a lens having a long focal length can be used, and the imaging performance is improved. In this invention, the mirror is integral with the substrate, and positioning of the mirror is unnecessary. Further, the orientation of the mirror is determined by the inclination of the end face of the substrate, and it is not necessary to adjust the orientation of the mirror (claim 1).

When multilayer wiring is provided on the transparent substrate via the resin film as in claim 2, wiring can be formed by etching a metal film (for example, copper foil) laminated on the resin film, and the wiring can be formed on the glass substrate. A vacuum process such as direct wiring formation is unnecessary. Therefore, there is no decrease in productivity due to the vacuum thin film process, and a large current wiring can be easily formed. For example, there is a wiring to the cathode drive IC in the case of dynamic driving as a portion requiring a large current wiring, but such wiring can be easily formed. Such multilayer wiring can be realized, for example, by a via sheet in which a sheet-shaped photosensitive resin and a metal foil are laminated, and the wiring forming process is the same as in the case of a hard printed board. Although the light emitting and receiving array requires considerably complicated wiring, the wiring can be easily realized by using the multilayer wiring. Next, since the transparent substrate is separated from the wiring of the first layer by the resin film of the first layer, there is no risk of contamination. Therefore, inexpensive soda glass or the like can be used for the substrate (claims 2, 3 and 4).

[0008]

Examples FIGS. 1 to 4 show an example of an LED head, FIGS. 1 and 2 show the structure of a substrate, and FIG.
Details of the layer wiring are shown in FIG. 4, and the structure of the entire LED head is shown. If another light emitting array is used instead of the LED array used in the embodiment, another image forming apparatus can be obtained, and if a light receiving array is used, it becomes an image sensor. The feature of the embodiment lies in the combination of the two-layer wiring shown in FIGS. 1 to 3 and the transparent substrate and the mirror shown in FIGS. 1 and 4, but not in the light emitting and receiving array itself. And even if the type of the light emitting and receiving array is changed, 1) the end face of the transparent substrate is cut obliquely to form a mirror, and the front width (width) of the image device is reduced, and
Use a transparent substrate as the optical path to lengthen the optical path so that a lens with a long focal length can be used. 2) When the light emitting / receiving array is flip-chip connected, the light travels through the transparent substrate, and the combination of the mirror and the transparent substrate is utilized. 3) Multi-layer wiring is provided on the transparent substrate to facilitate wiring to the light emitting / receiving array, 4) Multi-layer wiring is separated from the transparent substrate by the resin film to prevent contamination from the substrate and is inexpensive. The basic operation of the embodiment, which is to be used also in the substrate, does not change. In the embodiment, the two-layer wiring on the transparent substrate is shown, but this is an example of multilayer wiring.
Wiring of three layers or more may be used.

In FIG. 1 and FIG. 2, reference numeral 2 is a substrate and the whole substrate including wiring is used, and 4 is a transparent substrate, which is made of transparent glass or transparent plastic such as acrylic resin or epoxy resin. Since the transparent substrate 4 is shielded from the wiring by a photosensitive sheet as described later, when glass is used, it is not necessary to use a high-purity substrate such as borosilicate glass or quartz glass, and a substrate containing a large amount of impurities such as soda glass. However, the surface may be washed to remove the soda component (particularly its Na ions) deposited on the surface. When soda glass is used for the transparent substrate 4, a substrate with low cost and high surface smoothness and high shape accuracy can be obtained. Since the thermal expansion coefficient is small, the change in imaging performance due to temperature fluctuation is small and the heat resistance is high. Therefore, there is little deformation during flip chip connection. The thickness of the transparent substrate 4 is, for example, about 1 to 10 mm, preferably 3 to 1
It is 0 mm, more preferably 5 to 10 mm.

Reference numeral 6 denotes a mirror, which cuts the end surface of the transparent substrate 4 obliquely, and for example has an end surface 45 with respect to the main surface of the transparent substrate 4.
It is cut once and a mirror such as an aluminum film or a silver film is provided here by vacuum deposition or the like. The film thickness of the mirror 6 is, eg, about 0.2 μm to 3 μm.

Two layers of wiring are provided on one main surface of the transparent substrate 4 by using via sheets 8 and 10, and each via sheet 8 and 10 includes an adhesive layer and a sheet of a photosensitive resin and a copper foil or the like. In the state of the example, the photosensitive sheet is exposed and cured. Reference numeral 12 is a first layer wiring provided on the via sheet 8, 14 is a second layer wiring provided on the via sheet 10, and 16 and 18 are photosensitive sheets after exposure. The second layer via sheet 10 has a via hole (via
hole) 20 is provided and plating is applied to this portion to form a through hole for interlayer connection, and the wirings 12 and 14 are connected. Reference numeral 22 denotes a light transmission window provided on the via sheets 8 and 10 and is a long slit-shaped opening. Photosensitive sheet 16,
When it is transparent to the wavelength of the light used by 18, the light transmission window 2
2 is unnecessary. However, opaque photosensitive sheets 16 and 18
The provision of the light transmission window 22 by using the method has the effect of narrowing the emission beam from the LED array described later and removing stray light in advance by removing unnecessary light.

Reference numeral 24 is an LED array, the number of which is, for example, 40, and 26 is a light emitter thereof.
For example, 64 pieces are provided. 28 is a flip-chip connection bump, which is provided on the wiring 14 of the second layer,
The electrode pads on the D array 24 side are flip-chip connected. The bumps 28 may be provided on the LED array 24. Three
Reference numeral 0 denotes a cathode driving IC, which is an IC for driving the cathode (common electrode) of the LED array 24.

When glass is used for the transparent substrate 4 as in the embodiment, the photosensitive sheets 16 and 18 and the transparent substrate 4 have different coefficients of thermal expansion, and the transparent sheets 4 warp due to the temperature change due to the photosensitive sheets 16 and 18. there is a possibility. Therefore, via sheets 32 and 34 are provided on the main surface on the opposite side of the transparent substrate 4, and the via sheets 8 and 10 and the transparent substrate 4 are symmetrically arranged to prevent thermal deformation. In the embodiment, the same via sheets 8 and 10 are used as the via sheets 32 and 34. When plastic is used for the transparent substrate 4, the via sheets 32 and 34 are unnecessary because the thermal expansion coefficient is close to that of the photosensitive sheets 16 and 18. Also, when glass having a thermal expansion coefficient close to that of the photosensitive sheets 16 and 18 is used for the transparent substrate 4, the via sheets 32 and 34 are used.
Need not be provided. The role of the via sheets 32 and 34 is
Thermal stress that is almost the same as the thermal stress from the via sheets 8 and 10,
This is to act from the opposite main surface of the transparent substrate 4 to compensate for thermal stress and prevent thermal deformation. Beer sheets 32,3
Reference numeral 4 is a thermal stress compensation film for exerting a thermal stress in the opposite direction to the thermal stress from the via sheets 8 and 10. The via sheets 32 and 34 may be replaced with other ones as long as this action is obtained. For example, one layer of a photosensitive sheet for compensation is used as a via sheet 3
2, 34 may be used in place of the thermal stresses so that the generated thermal stress is almost balanced with the total thermal stress from the via sheets 8 and 10.

FIG. 3 shows the structure of the two-layer wirings 12 and 14. In the second layer wiring 14, 40 LED arrays 24
-1 to 24-40 U-shaped data bus 40 on both sides of the column
And the data bus 40 is configured in units of two LED arrays 24, the number of bits of which is 32 bits, and the data buses 40 above and below the columns of the LED arrays 24-1 to 24-40.
At 40, the array 24 is provided with the required 64-bit signal. Both ends of each individual wiring of the data bus 40 are terminated by flip chip bumps 28 and are connected to the LED array 24. 42 is a common electrode wiring, which is a cathode driving IC 30.
On the side, it is arranged in the gap between the data buses 40, 40. 44
Is a cathode drive wiring, which is a wiring for driving the cathode drive IC 30.

Moving to the wiring 12 of the first layer, 50 is an anode driving IC, 52 is a connector, and 54, 56 and 58 are wirings. Each wiring 54, 562, 58 is a via hole 2
It is connected to the data buses 40, 40, the cathode drive wiring 44, and the common electrode wiring 42 via 0, and only a part of the via hole 20 is shown in the figure. The data bus 40 on the upper side of the column of the LED array 24 is connected to each other via a wiring 54 and is also connected to the anode driving ICs 50, 50 at both ends. The same applies to the data bus 40 on the lower side of the column of the LED array 24, and the cathode drive wiring 44 is connected to the connector 52 and the anode driving ICs 50 and 50 via the wiring 56. The wiring 58 along the light transmission window 22 is connected to the common electrode wiring 42 through the via hole 20, and the data bus 4
It is insulated from 0 by the photosensitive sheet 18, and one LED array 2
The bumps for the common electrode are provided at two positions on both ends per 4 and flip chip connection is made at both ends to make the impedance between the common electrode and each light emitting body 26 constant.

As shown in FIG. 3, the light transmission window 22 is located at a position facing the row of the light emitters 26, is slit-shaped, and has a width of, for example, about 50 to 150 μm. The light transmission window 22 has a width slightly wider than the width of the light emitting body 26 in the direction of FIG. 2 (width in the sub-scanning direction), for example, the width of the light emitting body 26 expanded by 10 to 20 μm on both sides. The bumps 28 are provided outside the light transmitting window 22 by about 10 to 20 μm to prevent the width of the LED array 24 from increasing.

In the manufacturing method of the embodiment, the end face of the transparent substrate 4 is cut at 45 degrees, and after polishing, it is set in a large number of vapor deposition tanks and aluminum vapor deposition is performed to form the mirror 6. Next, the transparent substrate 4 is washed to remove Na ions and the like on the surface. Next, the unexposed via sheet 8 is attached, the photosensitive resin is applied again on the via sheet 8, and the first-layer wiring 12 is formed by exposure and etching. The via sheet is generally a laminate of an unexposed photosensitive sheet and an adhesive layer on a metal film such as a copper foil, and can be easily attached to the transparent substrate 4 with an adhesive. After that, the photosensitive sheet 16 in the light transmitting window 22 portion is exposed, developed, and removed. After the processing of the first layer is completed, the via sheet 10 of the second layer is attached, the wiring 14 of the second layer is similarly provided, the light transmitting window is provided in the photosensitive resin 18 of the second layer, and the via hole 20 is formed. Form. Then, while masking the portions other than the via holes 20, the via holes 20 are plated with copper or the like to connect the wirings 12 and 14. When the two-layer wiring is completed, bumps 28 are formed on the pads at the tip of the data bus 40 and the pads at the tip of the common electrode wiring 42, and the LED array 24 and the driving ICs 30 and 50 are flip-chip connected. Then, the exposed and cured via sheets 32 and 34 are attached. The two-layer wiring method and the exposure and etching methods themselves are arbitrary.

The thickness of the transparent substrate 4 is the same as that of the light transmitting window 2 in FIG.
It is determined by forming the data bus 40 on the upper side of 2, and when the thickness is small, the width forming the data bus 40 is lost.
This can be understood from FIG. 2, and if the thickness is small, the wiring area on the right side of the drawing becomes small, and this portion corresponds to the data bus 40 above the light transmission window 22 in FIG. Therefore, the thickness of the transparent substrate 4 is preferably 1 to 10 mm, more preferably 3 to 10 mm, and most preferably 5 to 10 mm.

FIG. 4 shows an overall image of the LED head. 6
Reference numeral 0 denotes a compound eye lens such as a self-focusing lens array or an array of various monocular lenses. Reference numeral 62 denotes a housing such as plastic or aluminum die casting, which is inexpensive and enhances the shield function. For example, a plastic housing is used and an aluminum foil or the like is provided on the surface. It is preferable that the metal conductive layer is provided on the surface by pasting, metal plating or vacuum deposition. As shown in FIG.
The light from the array 24 is reflected by the mirror 6, and the transparent substrate 4
The lens array 60 forms an image on the photoconductor drum or the like while proceeding through the inside.

The operation of the embodiment will be described. 1) Since the transparent substrate 4 is used, the light from the LED array 24 can be easily extracted. On the other hand, when a printed wiring board or the like is used, a long light transmitting window 22 must be provided on the printed wiring board, which makes processing difficult. 2) The transparent substrate 4 is the photosensitive sheet 16 and the wirings 12, 14 and L
It is shielded from the ED array 24 and is free from contamination by impurities. Therefore, an inexpensive substrate such as soda glass can be used. 3) Two-layer wiring for flip-chip connection of the LED array 24 can be easily realized by exposing the via sheets 8 and 10 and etching the copper foil. For example, the data bus 40 for flip chip cannot be configured with the single-layer wiring. 4) Since the LED array 24 is flip-chip connected using the transparent substrate 4, the light reflected by the mirror 6 can be made to travel inside the substrate 4 to form an image. With printed circuit boards, or wire bonding rather than flip chip, this is not possible. 5) The lateral width of the LED head is determined by the thickness of the transparent substrate 4, and the lateral width is reduced. On the other hand, in the conventional example, the width of the substrate 4 (the vertical width of the transparent substrate 4 in FIG. 4)
Then, the lateral width of the LED head is determined. Since the lateral width of the head is narrowed, the head can be easily attached to the photoconductor drum or the like, and can be easily attached to a drum having a small diameter. 6) The mirror 6 is integrated with the transparent substrate 4, and the LED array 24
If is mounted in the correct position, it means that the mirror 6 is correctly positioned. Therefore, it is not necessary to position the mirror. 7) The optical path length from the LED array 24 to the lens array 60 can be increased without increasing the width of the LED head. As is clear from FIG. 4, the optical path length increases as the width of the transparent substrate 4 increases. Therefore, a lens array with a long focal length can be used, and the LED
It is possible to reduce deterioration of the imaging performance due to an error in the position accuracy of the array 24.

[0021]

According to the present invention, the following effects can be obtained. 1) Since the mirror and the substrate are integrated, it is not necessary to position the mirror, and the angle adjustment of the mirror is also unnecessary (claim 1). 2) Use a mirror to reduce the front width of the imager,
Moreover, a lens having a long focal length can be used (Claim 1). 3) Since multilayer wiring is provided on the transparent substrate via the resin film,
There is no risk of wiring contamination by the substrate, and an inexpensive substrate can be used. Also, since the wiring is provided on the resin film,
By etching a metal foil provided on the resin film, a wiring having a large current capacity can be obtained without a thin film process. Since it is a multi-layer wiring, complicated wiring for the light emitting and receiving array can be easily realized (claims 2, 3 and 4). 4) The mirror can be realized by forming a film on the end face of the substrate, and the mirror can be easily obtained (claim 5).

[Brief description of drawings]

FIG. 1 is a cross-sectional view in the short side direction of a substrate of an image device according to an embodiment.

2 is a partially enlarged sectional view of FIG.

FIG. 3 is a plan view showing a state in which the two-layer wiring of the image device of the embodiment is disassembled.

FIG. 4 is a sectional view of the image device according to the embodiment.

[Explanation of symbols]

2 substrate 28
Bump 4 transparent substrate 30
Cathode drive IC 6 mirror 32, 34
Beer sheet 8, 10 Beer sheet 40
Data bus 12 First layer wiring 42
Common electrode wiring 14 Second layer wiring 44
Cathode drive wiring 16, 18 Photosensitive sheet 50
Anode drive IC 20 Via hole 52
Connector 22 Light transmitting window 54, 56, 5
8 wiring 24 LED array 60
Lens array 26 Light emitter 62
housing

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04N 1/036 A

Claims (5)

[Claims] 1. In an image device in which wiring is provided on a transparent substrate and a light emitting / receiving array is flip-chip connected to the wiring, an end face of the transparent substrate is formed obliquely and a mirror is provided on the end face. An imaging device characterized by: 2. A resin film is provided on the transparent substrate, a first layer wiring is provided on the resin film, and a second layer wiring is provided on the first layer wiring via a second resin film. 2. The image device according to claim 1, wherein the wiring of the first layer and the wiring of the second layer are connected to each other through a through hole provided in the second resin film. 3. The image device according to claim 2, wherein the transparent substrate is soda glass. 4. The light emitting / receiving array is an LED array, and a plurality of the LED arrays are arranged, and the second layer wiring is formed from a plurality of U-shaped data buses provided along both sides of a column of the LED array. 3. The image according to claim 2, wherein the first layer wiring is provided below the U-shaped data bus, and the U-shaped data bus is connected to the first layer wiring by the through hole. apparatus. 5. The image device according to claim 1, wherein the mirror is a metal film formed on an end surface of the transparent substrate.