JPH0667115A - Image device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to prevent the lens array from curving and form an image with high image quality on the photoconductor, or to generate an accurate electric signal corresponding to external image information in the solid-state image sensor array. An object of the present invention is to provide an image device capable of performing the above. A substrate 1 having an image element array 2 mounted in a housing 4 and an elongated lens array 3 having a large number of self-focusing lenses 8 arranged in a frame-shaped casing 7 are fixed at a predetermined interval. In this image device, the frame-shaped casing 7 of the elongated lens array 3 and the housing 4 have substantially the same thermal expansion coefficient.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an image forming apparatus such as an optical printer head or an image reading apparatus such as an image sensor, and more particularly to fixing a long lens array to a housing. .

[0002]

2. Description of the Related Art A conventional image forming apparatus, for example, an image forming apparatus used in an image forming apparatus such as an optical printer head, has a plurality of light emitting diode arrays formed of a plurality of light emitting diodes linearly arranged on an electrically insulating substrate. It is composed of a light-emitting element mounting substrate mounted in an array, a lens array in which a large number of rod-shaped self-focusing lenses are linearly arranged in two rows in a frame-like casing, and a housing made of polycarbonate resin, etc. Manufactured by fixing the element mounting substrate and the lens array with a predetermined distance between them and fixing each light emitting diode of the light emitting diode array through an adhesive so that each light emitting diode of the light emitting diode array is positioned on the optical axis of each self-focusing lens of the lens array. Has been done.

In such an image device, each light emitting diode of the light emitting diode array is caused to selectively emit light in response to an external electric signal, and the light emitted by each light emitting diode is passed through the lens array to the external photoconductor surface. It functions as an image forming apparatus by forming a latent image on the photoconductor by forming an image on.

[0004]

However, in this conventional imaging device, the long lens array is fixed to the housing by fixing the entire one side surface of the frame array casing of the lens array to the housing through an adhesive made of epoxy resin. What is done by bonding, and the frame-shaped casing of the long lens array is usually made of ABS resin or FRP.
In, also housing flatness, strength, considering price, etc. are formed of polycarbonate resin, larger thermal expansion coefficient of both the ^{0.9 ~ 6 × 10 -5 /℃,1.9 ×} 10 -5 / ℃ respectively Because of the differences, when this image device is used by incorporating it into an image forming device, when heat is applied to the housing and the lens array from the outside, a large thermal stress is generated at the bonding part between them and the lens array is 400 μm. As a result, there is a deviation between the optical axis of each self-focusing lens and the position of the light emitting diode, and the light emitted from the light emitting diode can be satisfactorily applied to the photoconductor through the self-focusing lens. However, it has a drawback that it is impossible to form a clear latent image on the photosensitive member accurately.

In the above-mentioned conventional example, an image device used in an image forming device such as an optical printer head has been described as an example. However, image reading by an image sensor or the like using a solid-state image sensor array (CCD element array). Even in the imaging device used in the device, etc., the image of the external image information on the solid-state imaging device array (CCD device array) becomes non-uniform due to the curvature of the lens array, and the image information is transferred to the solid-state imaging device array (CCD device array). It has a drawback that it is impossible to generate a corresponding accurate electric signal.

[0006]

SUMMARY OF THE INVENTION The present invention has been conceived in view of the above-mentioned drawbacks, and an object thereof is to accurately irradiate a photoconductor with light emitted from a light emitting diode through a lens array to form an image with high image quality on the photoconductor. Or an image device capable of accurately forming an external image information on a solid-state image sensor array through a lens array and generating an accurate electric signal corresponding to the external image information in the solid-state image sensor array. To provide.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a substrate having a picture element array mounted in a housing and a long lens array having a large number of self-focusing lenses arranged in a frame-shaped casing are arranged at a predetermined interval. An image device fixed, characterized in that the frame-shaped casing of the elongated lens array and the housing have substantially the same thermal expansion coefficient.

[0008]

According to the image device of the present invention, since the frame-shaped casing of the elongated lens array and the housing have substantially the same coefficient of thermal expansion, heat is externally applied to the housing and the elongated lens array. Even if this happens, a large thermal stress does not occur between them, and as a result, the lens array does not bend. Therefore, when this image device is used in an image forming device such as an optical printer head, the optical axis of each self-focusing lens of the lens array can be always located at the position of the light emitting diode, and the light emitted from the light emitting diode is directed to the photoconductor. It is possible to satisfactorily irradiate, and it is possible to form a clear and accurate latent image on the photoconductor.

When this image device is used in an image reading device such as an image sensor, since the lens array has no curvature, external image information can be accurately formed on the solid-state image sensor array through the lens array. It is possible to generate an accurate electric signal corresponding to the external image information in the solid-state image sensor array.

[0010]

The present invention will now be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment in which the image device of the present invention is adopted in an optical printer head as an image forming device, 1 is a substrate, 2 is a light emitting diode array, 3 is a lens array, and 4 is a housing. is there.

The substrate 1 is made of an electrically insulating material such as ceramic, glass or glass epoxy, and a plurality of light emitting diode arrays 2 are linearly mounted on the upper surface thereof.

The substrate 1 functions as a supporting member for supporting the light emitting diode array 2, and when it is made of, for example, a ceramic of aluminum oxide sintered material, alumina (Al ₂ O ₃ ) and silica (SiO ₂ ) are used. ₂ ), calcia (CaO), magnesia (MgO), etc.A suitable organic solvent is added to the raw material powder, and a solvent is added and mixed to form a sludge, and the conventionally known doctor blade method or calendar roll method is adopted. To obtain a ceramic green sheet (ceramic green sheet), and thereafter, the ceramic green sheet is punched into a predetermined shape and fired at a high temperature (about 1600 ° C.).

Further, the light emitting diode array 2 mounted on the substrate 1 is composed of a plurality of light emitting diodes 2a, and the light emitting diodes 2a selectively emit light in response to an external electric signal and emit light. A latent image for forming an image is formed on the photoconductor 5 by irradiating the surface of the photoconductor 5 with.

The light emitting diode 2a is a GaAsP type, Ga
P-based light-emitting diodes are used.For example, in the case of GaAsP-based light-emitting diodes, the GaAs substrate is first heated to a high temperature in a furnace and AsH ₃ (arsine), PH ₃ (phosphine), Ga (gallium) are used. ) Is contacted with a gas to grow an n-type semiconductor GaAsP (gallium arsenide phosphide) single crystal on the substrate surface, and then a Si ₃ N ₄ (silicon nitride) windowed film is formed on the GaAsP single crystal surface. It is attached and Zn (
It is formed by exposing a (zinc) gas to diffuse Zn into a part of the GaAsP single crystal of the n-type semiconductor to form a p-type semiconductor and having a pn junction.

In the case of the B4 optical printer head, 2048 (8 per 1 mm) light emitting diodes 2a are linearly arranged. Specifically, 64 light emitting diodes are used as one unit. By arraying 32 arrays 2 in a straight line, 2048 light emitting diodes 2a are arrayed on the substrate 1.

Further, the light emitting diode 2a is provided with a long lens array 3 on the upper part of the light emitting diode 2a at a predetermined interval, and the lens array 3 irradiates the surface of the photoreceptor 5 with the light emitted from each light emitting diode 2a. To act.

The long lens array 3 has a structure in which a large number of rod-shaped self-focusing lenses 8 made of glass, synthetic resin or the like are linearly arranged in two rows in a frame-shaped casing 7 for molding. Acrylonitrile butadiene styrene (ABS) resin, polycarbonate resin, polyphenylene sulfide (PPS) resin and other resin plates are sandwiched between rod-shaped self-focusing lenses 8 to accommodate them in two rows and silicone resin is dripped to cure the resin. Then, each of the self-focusing lenses 8 is bonded with a silicone resin and the frame-shaped casing 7 is formed.

The substrate 1 on which the light emitting diode array 2 is mounted and the lens array 3 also have a predetermined space between them, and the optical axes of the self-focusing lenses 8 of the lens array 3 are the light emitting diodes of the light emitting diode array 2. It is fixed to the housing 4 so that it is above 2a.

The housing 4 is made of acrylonitrile butadiene styrene (ABS) resin, polycarbonate resin, polyphenylene sulfide (PPS) resin, etc., and is a frame-shaped casing of the lens array 3 fixed to the housing 4.
Since the coefficient of thermal expansion is substantially the same as that of 7 (the coefficient of thermal expansion is exactly the same or similar), after fixing the lens array 3 to the housing 4,
Even if heat is applied to 3 from the outside, a large thermal stress due to the difference in thermal expansion coefficient between them does not occur between them, and as a result, the lens array 3 is bent due to the thermal stress. The lens array 3 fixed to the housing 4 can always position the optical axis of each self-focusing lens 8 on each light emitting diode 2a of the light emitting diode array 2, and
It becomes possible to irradiate the photoconductor 5 with the light emitted by the beam 2a accurately and clearly through the lens array 3.

The substrate 1 is fixed to the housing 4 by adhering the substrate 1 on which the light emitting diode array 2 is mounted inside the lower portion of the housing 4 with an adhesive 6 made of epoxy resin. The lens array 3 is fixed to the frame-shaped casing of the lens array 3.
7 and the housing 4 are fused and integrated by an ultrasonic welding method. In this case, the lens array 3
Since the frame-shaped casing 7 and the housing 4 are melted and integrated by the ultrasonic welding method, the lens array 3 is extremely firmly fixed to the housing 4.

Thus, according to the image device of the present invention, the substrate 1
An image is formed by causing the plurality of light-emitting diodes 2a linearly arranged above to selectively emit light in response to an external electric signal and irradiating the emitted light to the photoconductor 5 through the lens array 3. Functions as a device.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above-mentioned embodiments, the image of the optical printer head or the like is changed. Although the description has been given by taking the case where the light emitting diode array is used as a forming apparatus as an example, the light emitting diode array may be replaced with a solid-state image sensor array and used in an image reading apparatus such as an image sensor.

[0023]

According to the image device of the present invention, since the frame-shaped casing of the elongated lens array and the housing have substantially the same coefficient of thermal expansion, after fixing the elongated lens array to the housing, Even if heat is applied to both of them from the outside, thermal stress due to a difference in thermal expansion coefficient between them is hardly generated and the lens array is hardly curved. As a result, each self-focusing of the lens array is performed. Since the optical axis of the lens can always be located at the position of the light emitting diode, the light emitted from the light emitting diode can be satisfactorily applied to the photoconductor, and a clear and accurate latent image can be formed on the photoconductor. it can.

When this image device is used in an image reading device such as an image sensor, since the lens array has no curvature, external image information can be accurately formed on the solid-state image sensor array through the lens array. It is possible to generate an accurate electric signal corresponding to the external image information in the solid-state image sensor array.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment in which an image forming apparatus of the present invention is applied to an optical printer head as an image forming apparatus.

FIG. 2 is a cross-sectional view of the image forming apparatus shown in FIG. 1 taken along line XX.

[Explanation of symbols]

 1 ... substrate 2 ... light emitting diode array 2a ... light emitting diode 3 ... lens array 4 ... housing 6 ... .... Adhesive

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 33/00 N 7514-4M

Claims (1)

[Claims] 1. An imaging apparatus comprising: a substrate having an image element array mounted in a housing; and a long lens array having a large number of self-focusing lenses arranged in a frame-shaped casing and fixed at a predetermined interval. An image device, wherein the frame-shaped casing of the elongated lens array and the housing have substantially the same coefficient of thermal expansion.