JPS6215814B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a 1-magnification optical sensor, and particularly to a 1-magnification image sensor (hereinafter referred to as an image sensor) used in facsimiles and the like.

Many of today's image sensors have undergone significant development due to recent advances in semiconductor technology. In particular, the image sensor itself has become smaller due to the miniaturization of the photodiode, which is the light detection section. on the other hand,
Due to its nature, an image sensor requires an illumination light source to capture an image of the object to be detected (hereinafter referred to as a document), and in some cases requires an optical system to clearly capture the image. .

Fluorescent lamps, which are cold light sources, are representative of conventionally used illumination light sources. ) is currently available for image detection. In other words, although a fluorescent tube is normally columnar (tubular), its radiant flux is distributed radially from the center, so only a portion of the emitted light is irradiated onto the document. For these reasons, conventional lighting systems have poor lighting efficiency, do not work effectively in terms of power consumption, and have been forced to increase the capacity of the power supply circuit. In addition, in the case of an illumination system such as a fluorescent lamp, the entire device including the light detection section becomes large. If an LED array is used to solve these problems, it will reduce the size of the device, but there will still be problems with the efficiency of collecting reflected light.

Furthermore, if an optical system is used to focus the light flux from the illumination light source onto the original or to condense the reflected light from the original, the size of the apparatus inevitably increases due to the space required for its arrangement. Furthermore, it requires a great deal of effort, such as the need to adjust the focus of the light beam and take measures against vibrations of the original paper.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a 1-magnification image sensor that solves the above-mentioned problems, improves illumination efficiency, and makes it possible to downsize the device.

The main feature of the present invention is that a photodiode and an electroluminescent illumination light source are installed on the same transparent substrate, and the reflected light from the original is received without going through any optical system. .

The present invention will be described in detail below based on illustrated embodiments.

Example 1 ...See Figures 1 to 4.

FIG. 1 is an external perspective view showing an outline of the image sensor in this embodiment. In the figure, 1 indicates a transparent substrate. As the transparent substrate 1, a glass material having heat resistance and chemical resistance (for example, Corning #7740 or quartz glass) is suitable. 2 indicates a photodetector. This light detection section 2 is a transparent substrate 1
It is provided linearly in the longitudinal direction of the transparent substrate 1 on one side surface (upper surface in the figure). 3 indicates electroluminescence (hereinafter referred to as EL). The EL 3 is provided in a straight line on the other surface of the transparent substrate 1 (lower surface in the figure), facing the photodetector section 2 . 4 and 5 are metal electrodes for extracting a photodetection signal from the photodetection section 2.

FIGS. 2 and 3 show the arrangement of the photodetecting sections 2. FIG. That is, the photodetection section 2 is made up of a number of independent photodiodes 7 corresponding to the number of pixels to be detected in the document 6, which are arranged at a predetermined interval t from each other. This interval t is EL3 as described later.
It functions as a lighting window to let in the illumination light from the outside. On the other hand, EL3 is provided continuously.

FIG. 4 shows an example of the structure of the photodetecting section 2 and the EL 3 as a cross section along the line shown in FIG. Photodiode 7
For example, a --based heterojunction photodiode or an amorphous achalcogenite photodiode is used. In the example in Figure 4, Cds―CdTe―
It has a Te bonding structure. This photodiode 7 has Cds as its light receiving surface. Additionally, this photodiode 7 includes a blocking diode 8.
are integrated. The blocking diode 8 has a Cds-Te junction structure. 9 is a transparent electrode for connecting the photodiode 8 and the metal electrode 4, and SnO ₂ , InO ₃ or the like is used. The metal electrodes 4 and 5, photodiode 7, and blocking diode 8 described above are covered with a protective layer 10 of SiO ₂ . Note that Te serves as an electrode for coupling the photodiode 7 and the blocking diode 8 and also as a light shielding layer.

EL3 is typically made of Mn-doped ZnS, and SnO ₂ formed on the transparent substrate 1,
It is provided on a transparent electrode 11 made of In ₂ O ₃ or the like, and fixed using a metal electrode 13 of Al or the like as a counter electrode. SiO ₂ or the like may be provided on the EL 3 as the protective layer 12. Note that all of the above structures are formed of thin films.

Now, the image sensor according to the present invention is used in a state where the light receiving surface of the photodiode 7 is close to the surface of the document, as shown in FIG. The light emitted from the EL 3 passes through the transparent substrate 1, passes through the gap t between adjacent photodiodes 7, and is irradiated onto the document surface. The reflected light is directly incident on the light receiving surface of the photodiode 7.

Thus, by arranging the EL3 and the photodiode 7 on the same transparent substrate 1 as described above,
The illumination for the original 6 is provided by EL3 located close to it.
This can be carried out efficiently and with a sufficient amount of light, and the light detection can be carried out by directly receiving the light reflected by the original. With this configuration, it is possible to prevent the device from increasing in size due to the illumination and optical system as in the past, and to provide an image sensor that is extremely efficient and allows the device to be miniaturized.

Example ...See Figures 5 to 7.

This embodiment differs from the previous embodiment I in that the photodiode and the EL are arranged on the same surface of the same transparent substrate. That is, as shown in FIGS. 5 and 6, the EL is formed continuously on one side of the transparent substrate 1 (the top surface in the figure) in a straight line.
3, on which a photodiode 7 and a blocking diode 8 are laminated. This combination of photodiode 7 and blocking diode 8 is arranged with a predetermined interval t as in Embodiment I.

FIG. 7 shows the laminated structure of the photodiode 7 and the EL 3, taken along the cross section shown in FIG. Structure of photodiode 7 itself (Cds-CdTe-Te) and EL3
The structure itself (Mn-doped ZnS) is Example I
There is no difference. However, photodiode 7 and
An insulating film 14 made of SiO ₂ is interposed between the EL 3 and a transparent electrode 15 (SnO ₂ ,
In ₂ O ₃ ) is present. Since the other configurations are the same, they are designated by the same reference numerals as in Example I.

With this configuration, as shown in FIG.
The light emitted from the photodiode 3 passes through the gap t and is irradiated onto the original 6, and the reflected light is also directly received by the photodiode 7. Therefore, in the case of this embodiment, the light from EL3 is directly irradiated onto the document, so the illumination efficiency and photodiode 7 are
It is possible to further improve the light collection efficiency.

Example ...See Figures 8 to 13.

The features of the image sensor in this example are:
A photodiode and an EL are placed on the same surface of a transparent substrate, and the photodiode is arranged continuously, while the EL is arranged parallel to the photodiode at an appropriate interval, and when detecting light, each photodiode is arranged parallel to the photodiode.
The EL is configured to scan and drive, and a drive circuit for driving the EL is integrated and placed on the transparent substrate.

That is, FIG. 8 is an external perspective view showing an outline of the image sensor in this embodiment. In the figure,
31 indicates a transparent substrate. This transparent substrate 31
A suitable material is a glass material having heat resistance and chemical resistance (for example, Corning #7740 or quartz glass). 32 indicates a photodetector. The photodetector 32 is provided on one side of the transparent substrate 31 (the upper surface in the figure), and is provided continuously in a straight line in the longitudinal direction of the transparent substrate 31.

Here, the photodetector 32 has a number of photodiodes 34 corresponding to the number of pixels to be detected of the original 33 that are individually and continuously arranged (that is, in an electrically insulated state). It is. As the photodiode 34, a --based heterojunction photodiode, an amorphous ascalcogenite photodiode, or the like is used. In this embodiment, as shown in FIG. 9, a Cds-CdTe-Te laminated structure is used. 35 is a metal electrode such as Au.

36 indicates EL. The EL 36 is made up of a number of ELs corresponding to the number of pixels arranged parallel to the photodetector 32 with a predetermined interval between them. EL
ZnS or the like is used as the material 36, and as shown in FIG. 9, it is fixed adjacent to the photodiode 34 together with a metal electrode 37 made of Au or the like.

The above photodiode 34 and EL 36 are provided on a thin film transparent electrode 38 made of SnO ₂ or the like formed on a transparent substrate 31, and this electrode 38 is used as a common electrode. In FIG. 9, a black body slit 3 is provided on the other side of the transparent substrate 31 (lower surface in the figure).
9, which is opened in a slit shape at a portion corresponding to the light receiving surface (Cds surface) of the photodiode 34. This slit 42 is used as a detection window for the original 33.

40 indicates a light emission scanning drive circuit for the EL36. This drive circuit 40 is integrated and placed on the transparent substrate 31. An example of the drive circuit 40 is shown in FIG. The drive circuit 40 includes a diode matrix circuit connected to each EL 36 and a switching circuit S _A to S _D , S ₁ that selects the EL to be driven.
~S _o and a scanning circuit 41 that sequentially scans this switching circuit.

The scanning circuit 41 uses, for example, a shift register, a multiplexer, a ring counter, etc., and sends a scanning signal with the timing shown in FIG. 12 to each switch S.
Give to _A to S _D and S ₁ to S _o . In other words, Switch S ₁
~S _o is connected to a predetermined number of EL36 as one group (four in Fig. 11), for example, the 12th
When the signal _S1 in the figure is at the "High" level, the switches S _A to S _D sequentially go to the High level, causing the EL 36 to light up sequentially from the left. In addition, Z
_A to Z _D is the load resistance when EL36 is lit, Ps
is the power supply. This power source is a DC or AC power source depending on whether the EL 36 is a distributed DC or an AC driven intrinsic EL. The waveform in that case is shown in FIG. The broken line DC is the waveform for DC drive, and the solid line AC is the waveform for AC drive.

In the above configuration, the EL
The light emitted from 36 passes through transparent substrate 31 and is irradiated onto document 33 through slit 42 . The reflected light passes through the transparent substrate again to the photodiode 3.
The light is incident on the Cds surface of 2 and is photoelectrically converted. The output signal of photodiode 32 is amplified by amplifier 43 and then input to video signal generator 44 .

In this way photodiode 32 and EL3
By arranging the EL 36 and the EL 6 in close proximity on the same transparent substrate 31, the light from the EL 36 can be efficiently irradiated onto the document, and since it is illuminated and received close to the document, it can be reliably illuminated with low power consumption. The image can be detected. Therefore, the lighting efficiency can be improved and the device can be significantly downsized.

Figure 10 shows the EL36 in the embodiment of Figure 9.
In order to reduce the influence of scattered light and diffracted light from
A recess 45 is formed in the transparent substrate 31, and the bottom of the recess 45 is inclined at θ° as shown in the figure to improve the S/N ratio. The rest of the structure is the same as that in FIG. 9, so a description thereof will be omitted.

As described above, according to the present invention, by providing a photodiode as a photodetecting element and an electroluminescent device as an illumination light source on the same transparent substrate, an optical system for large-scale illumination and light condensing, etc. It is possible to provide a 1-size optical sensor that eliminates the need for a 1-size original image, can obtain an original image at 1-size magnification, has improved illumination efficiency, and can significantly reduce the size of the device used.

[Brief explanation of the drawing]

1 to 4 show Example I of the present invention, and FIG. 1 is an external perspective view showing an outline of the image sensor,
Fig. 2 is a partially enlarged sectional view showing the arrangement of photodiodes, Fig. 3 is a plan view of the same, and Fig. 4 is a sectional view showing the structure of photodiodes and electroluminescence as seen from the cross section in Fig. 3. . 5 to 7 show examples of the present invention, FIG. 5 is a partially enlarged cross section showing the arrangement of photodiodes and the formation of electroluminescence, FIG. 6 is a plan view of the same, and FIG. Figure 6 -
FIG. 2 is a cross-sectional view showing the structure of a photodiode and electroluminescence in cross section. Figure 8-1
3 shows an embodiment of the present invention, FIG. 8 is an external perspective view showing an overview of the image sensor, FIG. 9 is a sectional view showing the structure of a photodiode and electroluminescence, and FIG. 10 is a diagram showing an electroluminescence structure. Cross-sectional view showing an example of the structure when tilted, No. 11
The figure is a circuit diagram showing an example of an electroluminescence light emission scanning drive circuit, FIG. 12 is a timing chart of an electroluminescence drive signal, and FIG.
The figure is a waveform diagram showing an example of the waveform of a drive signal. DESCRIPTION OF SYMBOLS 1... Transparent substrate, 2... Photodetection part, 3... Electroluminescence, 6... Original, 7... Photodiode, 31... Transparent substrate, 32... Photodetection part, 33... Original, 34... Photodiode, 36... Electroluminescence sense.

Claims (1)

[Scope of Claims] 1. A transparent substrate, a photodiode formed on a first surface of the transparent substrate on the side to be detected, and a photodiode formed on a second surface of the transparent substrate opposite to the first surface. The light emitted from the electroluminescence passes through the transparent substrate and reaches the object to be detected, and the light reflected by the object to be detected is reflected by the photodiode. A 1x optical sensor that is characterized by the ability to receive light.