JPH0679086B2 - Light emitting / receiving mechanism for facsimile - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a light emitting / receiving mechanism for a facsimile, which is suitable for miniaturization.

[Background of the Invention]

Conventional structures for obtaining a linear light source include a straight tube fluorescent lamp and an alternative LED array. Also recently LED
Fax with a Fresnel lens array on the output side of the array
Commercial linear light sources are commercially available, and the optical path length is being shortened and miniaturized. However, these are not enough in terms of efficiency and cost performance. Further, an idea for erasing bit information by shaping the intensity distribution of laser light of an optical disk device into an elliptical shape and irradiating it on a recording medium has been proposed by JP-A-59-68844 et al. It is drawing attention as a method that can be written. However, in the lens of the known example, the means for shaping the optical shape into an elliptical shape is not necessarily simple, the optical system becomes complicated, and it is not easy to form an arbitrary beam shape.

[Object of the Invention]

An object of the present invention is to provide a light emitting section having a linear light source lens for linearly expanding a point light source in a wide range, and a small light receiving section for receiving reflected light reflected from a document illuminated by the light of the light emitting section. Another object of the present invention is to provide a light emitting / receiving mechanism for a facsimile machine.

[Outline of Invention]

The linear light source lens used in the light emitting portion of the facsimile light emitting / receiving mechanism of the present invention will be described with reference to FIGS. 1 and 2.

In the figure, reference numeral 21 denotes a lens plate in which a transparent plate is provided with a refractive index distribution to form a periodic striped pattern. For example, the striped pattern has a gradually smaller outside. Further, if the pitch in the x direction is made denser than in the y direction, the point light source on the left side L1 of the lens plate 21 is linearly focused like L2 on the right side. A detailed view is shown in FIGS. 1 (C) and (D). FIG. 1 (C) shows a transparent substrate 21.
A substance 211 that gives a change in light transmittance is injected therein. For example, the substrate 21 is a glass material, and the injected substance 211 is a metal ion such as Ag. For these impurity ions, the glass substrate heated to a temperature below the melting point is dipped in a molten salt such as silver phosphide, masked on the glass substrate except the region to be injected, and an electric field is applied between the substrate and the molten salt. By giving it, metal ions are implanted into a portion other than the mask. After that, if the mask is removed, a refractive index distribution can be created in the transparent plate. The pitch of the impurity-implanted portion is made different in the horizontal direction and the vertical direction, but the regularity of gradually decreasing toward the outside is the same. That is, by setting the vertical and horizontal dimensions of the rectangular pattern formed in the central portion to different values, a linear light condensing function having two focal points can be obtained as shown in FIG. 1 (A). In the description, the side where the refractive index distribution is formed in the glass substrate has been described. However, by coating the transparent substrate with a plastic film and removing a part thereof, it is possible to form a lens having a binary cross-sectional shape.

FIG. 1 (D) shows this example. For example, a PMMA (polymethylmethacrylate) thin film 212 is formed on the transparent substrate 21 by a photolithography process.
The regularity of the repetitive pitch is the same as the example of FIG. 1 (C). An example of this process is (1) PM on the glass substrate 21.
Make a few drops of MA in a liquid state, and coat the entire surface with a spinner so that the film thickness is about 1 μm. (2) After that, pre-baking is performed, and (3) exposure is performed through a shadow mask having a required repeated pitch prepared separately. The black part of the shead mask does not transmit light, so PM
Although it does not change the MA at all, the light passing through the transparent part of the mask crosslinks the PMMA molecules and strengthens the molecular structure of this part. Therefore, when it is immersed in an aromatic organic solvent and developed, only the pattern of the exposed portion remains. (4)
Further, post baking is performed at a slightly higher temperature to strengthen the remaining portion. Through the above process, a pinner type micro Fresnel lens made of a plastic film can be manufactured. The principle of the lens action will be described. This can be understood from the diffraction development of the Fresnel zone plate shown in FIG. 2 (A). The Fresnel zone plate is designed so that the diameter Rn of the n-th band is given by the following equation, as shown in the plan view of FIG.

Here, n: natural number λ: wavelength of light F: focus of lens In this case, the + 1st order diffracted light is focused on the right focus F of the lens plate 21 because the fringe pattern is concentric. In the case of A), the twist from the center of the n-th line of the rectangular striped pattern may be repeatedly formed at a cycle satisfying the relationship of the expression (1). In addition, set the focal length in the x and y directions to Fy> Fx
By doing so, linear light elongated in the x direction can be obtained as diffracted light. However, as shown in FIG. 2 (A), it is not possible to focus all the -1st order light and the 0th order light on the focal point by only the diffraction development. Therefore, the cross-sectional shape of the transport belt may be such that a triangular blazed shape as shown in FIG. 2 (B) has a higher light-collecting efficiency than a rectangular shape as shown in FIG. 2 (A).

By using this Fresnel lens, a micro lens having a planar shape with high shape dimension accuracy can be formed on the light emitting diode (or laser diode) 22 through the space or the transparent material 210 as shown in FIG. If provided as 21, it can be mounted on the metal case 25 of the heat sink to realize a compact linear light source.

Specific dimensions of the lens shown in FIG. 1 (D) are shown below.

(1) From the x-direction focus Fx = 4mm (2) From the y-direction focus Fy = 20mm (3) Overall size 2mm × 2mm (4) From the center of the nth stripe Here, λ is a light source length of 660 nm.

(5) Pitch of outermost peripheral line x direction: 0.6 (μm) y direction: 1.3 (μm) (6) Number of lines x direction: 75 lines y direction: 377 lines When such a lens is used, FIG. 1 (E) By arranging as shown in, it is possible to expand the emission light source in 2 mm to a linear light with a width of 8 mm.

Example of Invention

 Examples of the present invention will be described below.

FIG. 3 shows a schematic structure of a light emitting / receiving mechanism for a facsimile using the linear light source lens described in FIG. Third
The figure shows a method of reading with the photodiode array 1 having a close contact structure with the shortest optical path length, and one light source. The lens 21 for the linear light source can effectively irradiate the linear light on the document 20 simply by providing the lens 21 for the point light source such as the LED. Therefore, the information written on this can be read by the photodiode array as the reflected light amount. You can The detailed structure and function will be described below. FIG. 4 shows an embodiment of the present invention. In the figure,
There is a transparent substrate 10 arranged so as to face the original document 20, and a main surface of the transparent substrate 10 on the original document 20 side is covered with a light-shielding film 6 obtained by vapor-depositing Cr or the like. Has a window 6A formed by, for example, a selective etching method. A transparent insulating film 5 made of, for example, SiO _{2 is} formed on the light shielding film 6 including the window 6A by a CVD method or the like. Further, an electrode 8 formed by vapor-depositing Al, for example, is formed on the upper surface of the transparent insulating film 5, the photodiode 1 is mounted on one end of the electrode 8, and the other end is formed by extending the pressure in one direction. Has been done. The photodiode 1 is made of a semiconductor material having a PN junction, and is covered with an insulating film 4 (eg, SiO ₂ ) except for the light irradiation portion on the surface on the side of the original 20. Further, a transparent conductive material made of, for example, ITO is applied to the light irradiation portion of the photodiode 1 to form an electrode 7, and the electrode 7 is formed.
Are formed so as to extend in the direction opposite to the electrode 8. Thus, as shown in the plan view of FIG. 5 (B), the photo sensor portion including the photo diode 1 and the electrodes 7 and 8 connected to the photo diode 1 is arranged in the direction orthogonal to the extending direction of the electrodes 7 and 8. It consists of a number of juxtaposed structures. A transparent substrate made of glass or a transparent resin material is covered with the photodiodes 1 in a state where the other ends (electrode extraction portions) of the electrodes 7 and 8 are exposed.
31 is formed, and a lens 3 is formed on each photodiode 1 on the main surface of the original 20 side. The lens 3 has a focal length that matches the plate thickness of the transparent substrate 31, and is formed by a photo-etching method used in a semiconductor manufacturing process or the like. That is, for example, a mask is formed of a photoresist film except for the lens forming region, and Th or As ions are diffused to the transparent substrate 31 side from the window of the mask.
Then, the Th or Ag ions are diffused and formed in the concentric pattern described in FIG. 2 with a material having a refractive index different from that of the transparent substrate 31, so that the individual sensors 1 as shown in FIG. The lens array 3 is configured corresponding to. The light source 2 is arranged on the back side of the transparent substrate 10, and the arrangement is as follows.
The light source light is set so that it can illuminate the surface of the original 10 through the window 6A of the shielding film 6 and illuminate the photodiode 1 through the lens 3. The irradiation light on the document surface has only to cover the size of the sensor 1, and it is desirable that the intensity is high. It is the first to realize such conditions with the fewest number of light sources.
It is preferable to use the linear light generated by the linear light source lens shown in the figure. In FIG. 4 (C), the sensor pitch p
I draw an example of arranging one LED in twice as many as
When the light emission speed is high, it is possible to irradiate one light source out of 3 to 5 light sources as linear light over the entire paper width by the bifocal lenses 211 and 212. At this time, it is desirable to consider the position of the LED light source so that the window 6A focuses in the x direction, but the light-shielding film may be formed in the required size. The light projected from the light source 2 configured in this way is effectively projected as a linear light over the entire reading line of the original document 10, and the reflected light is reflected by the lens 3 onto the upper surface of the corresponding photodiode 1. Collected. The output voltage of the photodiode 1 is output in response to the image written on the original 20 and transmitted to a signal processing unit (not shown).

FIG. 5 shows another embodiment of the image sensor according to the present invention and shows a structure in which a photo sensor array is formed on the back side of the transparent substrate 10. The same reference numerals as those in FIG. 3 indicate the same materials. With this structure, the microlens array 3 can be manufactured regardless of the surface on which the photosensor array 1 is provided.
The thickness of the transparent substrate 10 may be made to match the focal point of the lens 3 without any restrictions in consideration of matching in the manufacturing process of both. The Fresnel lens 3 is based on the principle shown in FIG. 2, and is produced by finely processing a transparent optical thin film (about 1 .mu.m thick) to about 1 .mu.m in the outer peripheral ring zone pitch using an electron beam drawing apparatus.

The array of Fresnel ring zones may have a planar shape corresponding to the photodiode 1 as shown in FIG. 6B, but even if they have mutually trapped shapes as shown in FIG. It has been confirmed experimentally that there is. This method, which uses a planar microlens array, has the feature that a compact and bright image sensor can be obtained. Further, this structure is advantageous in terms of accuracy, variation, and cost because a mass production method using a semiconductor process can be adopted in mass production.

As another method, on the glass substrate 31, a circular film made of, for example, a synthetic resin is sequentially deposited with its diameter reduced by a photo-etching method, and then the deposited synthetic resin body is heated and melted, and The semi-convex lens may be formed by utilizing the flow. The light source 2 can be similarly used in any of the embodiments, and since the lens 21 can be formed on the transparent substrate by using the semiconductor fine processing process, the focus distance is, for example, 0.1.
It can be made as small as ~ 5mm, and the pitch between each diode 1 is 1
Since it can be made as small as 25μ, the optical path length is 0.2-10 mm, which is 1
It is possible to approach the perfect contact type shown in the example, and it is promising as a small-sized fax light source.

〔The invention's effect〕

As described above, according to the present invention, a light emitting / receiving mechanism for a facsimile has a light emitting portion having a thin film linear light lens that forms linear light from a point light source, and collects reflected light from a document. Since it is composed of a condenser lens and a light receiving part that has a thin film photosensor that receives the condensed light, it is possible to emit light again by associating multiple photosensors with one linear light lens. By forming the components of the light receiving unit and the light receiving unit into thin films, the light emitting / receiving mechanism for facsimile can be downsized, and the facsimile apparatus can be downsized and lightweight.

[Brief description of drawings]

FIG. 1 is a diagram showing the principle and structure of a linear light source lens used in the present invention, and FIG. 2 is a Fresnel zone plate (lens).
FIG. 3 is a schematic configuration diagram of the present invention, FIG. 4 is a detailed diagram showing a configuration of an embodiment of the present invention, and FIG. 5 is a detailed diagram showing a configuration of another embodiment of the present invention. , FIG. 6 is a diagram showing a Fresnel lens array. 2 ... Transparent substrate, 21 ... Lens.

Claims (1)

[Claims] 1. A light emitting element as a point light source, a transparent substrate containing the light emitting element, and an XY formed on the front surface of the transparent substrate.
A light emitting section comprising a thin film linear light lens having regularly different synchronous fringe patterns in two directions and having different focal lengths in the two directions, and an original document irradiated with linear light from the light emitting section Another transparent substrate facing the same, and a thin-film light condensing light which is formed on one surface of the transparent substrate facing the document and has a concentric circular pattern of synchronization stripes to collect reflected light from the document. A lens, a thin-film photosensor formed on the other surface of the other substrate to receive light from the condenser lens, and a light-shielding film that shields the periphery of the photosensor and has a window adjacent to the photosensor And a light-receiving part consisting of the light-emitting part, the light-emitting part being located on the other surface side of the another substrate and radiating linear light through the window, and one of the light-emitting parts is provided with a plurality of sets of the light-collecting parts. The lens and the photo sensor are compatible with each other. Shimiri for a light-emitting and receiving mechanism.