JPH01179564A - image sensor unit - Google Patents

Abstract

PURPOSE:To detect only an optical signal from a reading surface with an image sensor by providing a transparent substrate, for which a transparent conducting film is formed between an electric discharge lamp and the image sensor, and connecting the transparent conducting film to a grounding part. CONSTITUTION:A light from an electric discharge lamp 7 passes through an aperture 5 and arrives at a reading surface 8 of an original 3 and a reflected light from the reading surface 8 successively passes through a 'Selfoc(R)' lens 9, a transmitting light hole 10 and a transparent substrate 11 and arrives at an image sensor 12. At such a time, the light in a condition to pass through the transmitting light hole 10 includes the radiating noise of the electric dis charge lamp 7, however, the radiating noise is absorbed by the transparent conducting film of the transparent substrate 11 and caused to fall down through a unit substrate 6 and a frame 2 to a ground. Thus, the light to pass through the transparent substrate 11 goes to be an optical signal component, for which the radiating noise of the electric discharge lamp 7 is removed. Then, the condi tion of the reading surface 8 of the original 3 to be changed to be black or white can be detected in a stable condition.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an image sensor unit used in facsimile machines, copying machines, and the like.

2. Description of the Related Art In general, this type of image sensor unit includes a discharge lamp that illuminates the reading surface of a document, an image sensor that detects reflected light from the reading surface, and a drive circuit that drives the image sensor. An output signal is obtained by photoelectrically converting an optical signal from a document using an image sensor using a photoelectric conversion element.

Problems to be Solved by the Invention The light received by the image sensor includes a drive frequency component of the discharge lamp. Therefore, in the reflected light from the document surface, as shown in FIG. 6, the optical signal B of the document is superimposed on the drive frequency component A of the discharge lamp that undulates greatly. Therefore, it is difficult to remove the radiation noise of the discharge lamp from the signal detected by the image sensor, and there is a problem in that only an output signal containing the radiation noise can be obtained.

Means for Solving the Problems An image sensor unit includes a discharge lamp that illuminates the reading surface of a document, an image sensor that detects reflected light from the reading surface, and a drive circuit that drives the image sensor. A transparent substrate on which a transparent conductive film was formed was provided between the discharge lamp and the image sensor, and the transparent conductive film was connected to a ground portion.

The radiation noise from the active discharge lamp is a type of electromagnetic wave, and the radiation noise component included in the reflected light from the reading surface of the original is absorbed by the transparent conductive film of the transparent substrate and dropped to the ground, so that there is no fluctuation component. Only the optical signal from the reading surface will be detected by the image sensor.

Embodiment A first embodiment of the present invention will be explained based on FIGS. 1 to 3. First, the image sensor unit 1 has a conductive frame 2, and the upper part of this frame 2 is connected to a document 3.
The contact surface 4 has an opening 5 formed therein. A conductive unit base 6 is attached within the frame 2, and a discharge lamp 7 for illumination is attached to this unit base 6. Further, a SELFOC lens 9 is attached so as to face the reading surface 8 of the document 3 located in the opening 5, and a transmitted light hole 10 is formed at the other end of this SELFOC lens 9.

A transparent substrate 11 made of an insulating material is attached below this transmitted light hole 10.
1, an image sensor 12 formed in the shape of a substrate is provided. Further, a drive circuit 13 formed of a printed wiring board for driving the image sensor 12 is provided on the lower surface of the unit base 6. Next, a transparent conductive film 14 is formed on the upper surface of the transparent substrate 11, and this transparent conductive film 14 is in contact with the unit base 6.

Further, the frame 2 with which the unit base 6 is in contact is grounded by means such as a conductive wire (not shown).

In such a configuration, the light from the discharge lamp 7 reaches the reading surface 8 of the original 3 through the opening 5, and the reflected light from the reading surface 8 is transmitted through the Serafoc lens 9, the transmitted light hole 1o, and the transparent substrate 1.
1 and reaches the image sensor 12. At this time, the light passing through the transmitted light hole 10 includes radiation noise from the discharge lamp 7, as shown in FIG.
The radiation noise is absorbed by the transparent conductive film 14 of the transparent substrate 11, passes through the unit base 6 and the frame 2, and is dropped to the ground. Therefore, the light passing through the transparent substrate 11 is
Only the optical signal component from which the radiation noise of the discharge lamp 7 has been removed is left, and the state in which the reading surface 8 of the document 3 changes to black or white is detected in a stable state.

That is, when the reading surface 8 of the original 3 is white, a flat output as shown in FIG. 3 is obtained.

Of course, if the reading surface 8 is black, the signal output in FIG. 3 will be reduced.

Next, a second embodiment of the present invention will be described based on FIG. 4. In this embodiment, a transmitted light hole 16 is formed in a conductive unit substrate 15, and a transparent substrate 17 and an image sensor 8 are laminated and held by this unit substrate 15. The transparent substrate 17 is made of an insulating material, and a transparent conductive layer 19 in contact with the unit base 15 is formed on the lower surface thereof. Further, in the image sensor 18, a light shielding layer 21 is formed on the upper surface of a transparent image sensor substrate 20, and a through hole 22 corresponding to the transmitted light hole 16 is formed by this light shielding layer 21. A transparent insulating layer 23 is laminated on such a light shielding layer 21,
A photoelectric conversion element 24 is formed on the upper surface of this insulating layer 23. A document 26 with the reading surface 25 facing downward is placed on top of the document.

Next, below the transmitted light hole 16, a discharge lamp 28 for illumination supported by a support member 27 is provided.

In such a configuration, the light from the discharge lamp 28 passes through the transmitted light hole 16, the transparent substrate 17, the image sensor substrate 20, the through hole 22, and the insulating layer 23, and reaches the reading surface 25 of the document 26. The reflected light reaches the photoelectric conversion element 24 and the signal is read. Thus, when the light containing radiation noise from the discharge lamp 28 passes through the transparent substrate 17, the radiation noise is absorbed by the transparent conductive layer 19 and dropped to the ground via the unit substrate 15. Therefore, the optical signal read by the photoelectric conversion element 24 does not contain radiation noise, and stable reading is performed.

Next, a third embodiment of the present invention will be described based on FIG. The same parts as those described in the second embodiment described above are designated by the same reference numerals, and the description thereof will be omitted. This embodiment uses an image sensor 29 that is different from the image sensor 18 of the second embodiment. That is, a photoelectric conversion element 31 is formed on the upper surface of an image sensor substrate 30 that also acts as a transparent substrate, a transparent conductive layer 32 is formed on the lower surface of the image sensor substrate 3o, and this transparent conductive layer 32 is a conductive unit. It is in contact with the substrate 15.

Therefore, the radiation noise contained in the discharge lamp 28 is absorbed by the transparent conductive layer 32, and a flat optical signal can be obtained.

Effects of the Invention As described above, the present invention provides an image sensor that includes a discharge lamp that illuminates the reading surface of a document, an image sensor that detects reflected light from the reading surface, and a drive circuit that drives the image sensor. In the unit, a transparent substrate on which a transparent conductive film is formed is provided between the discharge lamp and the image sensor, and the transparent conductive film is connected to the ground, so that the noise radiated from the discharge lamp is a type of electromagnetic wave. Therefore, the radiation noise component included in the reflected light from the reading surface of the document is
This has the effect that only the optical signal from the reading surface, which is absorbed by the transparent conductive film of the transparent substrate and dropped to the ground, and has no fluctuation components, is detected by the image sensor.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional side view showing the first embodiment of the present invention, and the second
The figure is a perspective view of the transparent substrate, FIG. 3 is a waveform diagram with radiation noise removed, FIG. 4 is a longitudinal cross-sectional side view showing the second embodiment of the present invention, and FIG. 5 is the third embodiment of the present invention. FIG. 6 is a vertical side view showing an embodiment of the present invention, and FIG. 6 is a waveform diagram in a state where radiation noise is included. 3.26...Manuscript, 7,28...Discharge lamp, 8.25
...Reading surface, 11,20.30...Transparent substrate, 12
゜18.29...Image sensor, 13...Drive circuit, 14.19.32...Transparent conductive layer l, l Figure 19, 3 Figure time -

Claims (1)

[Claims] An image sensor unit including a discharge lamp that illuminates a reading surface of a document, an image sensor that detects reflected light from the reading surface, and a drive circuit that drives the image sensor, wherein the discharge lamp and the image sensor are connected to each other. An image sensor unit comprising: a transparent substrate having a transparent conductive film formed therebetween; and the transparent conductive film is connected to a grounding part.