JPH0690329A - Optical device and original reader using same - Google Patents

Abstract

PURPOSE:To simplify the circuit and to reduce the cost by providing a light source having a spectral characteristic opposite to a spectral sensitivity characteristic of a charge coupled element so as to make an output intensity of the charge coupling element constant without use of a filter. CONSTITUTION:A light radiating from a fluorescent light 11 is reflected in a reflecting mirror 13, passes through an original support member 15 and radiates to an original 12. The reflected light from the original 12 is converged by a rod lens array 16, and made incident in a color CCD 17, in which the light is converted into a voltage. Then the converted voltage is processed by a signal processing circuit 19 via an amplifier 18 and a color picture is reproduced. Through the constitution above, the fluorescent light 11 having a spectral characteristic in the order of red>green>blue opposite to a spectral sensitivity characteristic of the CCD 17 in the order of blue>green>red is employed. The spectral characteristic level of the fluorescent light 11 is set to have a desired characteristic by changing the blending ratio of fluorescent materials. Thus, no filter is required and the number of components is educed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device and a document reading apparatus using the same, and more particularly to an optical device having a charge-coupled device as a photoelectric conversion device used in a color copying machine or a facsimile machine and the device. A document reading apparatus using

[0002]

2. Description of the Related Art Conventionally, an optical device used in a document reading device such as a color copying machine or a facsimile device is shown in FIG. In FIG. 4, the tube-shaped halogen bulb 1 elongated in the depth direction emits the emitted light to the original 2
In order to efficiently irradiate the light in a specific direction, it is arranged at the focal position of the reflecting mirror 3 which is formed in a gutter-shaped cross section and whose inner surface is subjected to thin film aluminum vapor deposition.

Metal terminals (not shown) are fixed to both ends of the halogen bulb 1, and the halogen bulb 1 is supplied with a current from the DC power supply 4 to the metal terminals.
Lights up and emits light. The emitted radiated light is reflected by the reflecting mirror 3 and is made of glass or the like.
Then, the original 2 is irradiated with the light.

The light reflected by the original 2 is narrowed down by the rod lens array 6 and enters the color CCD (charge coupled device) 8 through the filter 7 to be converted into a minute voltage value. The converted voltage is amplified by the amplifier circuit 9 and then output to the signal processing circuit 10. Then, in this signal processing circuit 10, a color CCD
By processing the red (R), green (G), and blue (B) signals output from No. 8, a color image is reproduced.

[0005]

In the above-mentioned optical device, in order to make the output intensities of red (R), green (G), and blue (B) of the reflected light almost constant, the filter 7 is transmitted, The output voltage from the color CCD 8 is made substantially the same to obtain a state where post-processing is easy.

Incidentally, as shown in FIG. 5, the spectral characteristic of the halogen bulb 1 decreases in the order of red (R), green (G), and blue (B), and the spectral sensitivity characteristic of the color CCD 8 also decreases. Similar to the halogen bulb 1, the spectral sensitivity decreases in the order of red (R), green (G), and blue (B) as shown in FIG. 6, so that the output of the color CCD 8 is red (R) as shown in FIG. ), Green (G), and blue (B) in that order, and as a result, it was necessary to dispose the filter 7.

However, when this filter 7 is used, there is a problem in that it is necessary to increase the mounting accuracy for reflected light and the number of parts is increased, resulting in a high price.

Further, in a document reading apparatus such as a color copying machine or a facsimile apparatus using the above-mentioned optical device, when the filter 7 is not used, a correction circuit is provided so that the red color output from the CCD 8 ( Although the spectral sensitivities of R), green (G), and blue (B) are corrected, the provision of the above-described correction circuit complicates the circuit and increases the cost.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical device in which the output intensity from the charge-coupled device is constant even when a filter is not used.

Another object of the present invention is to:
An object of the present invention is to provide a document reading device which simplifies the circuit and reduces the cost.

[0011]

In order to solve the above-mentioned problems, an optical device according to the present invention is a charge-coupled device for converting light into an electrical signal, and a spectral sensitivity characteristic of the charge-coupled device. And a light source having a spectral characteristic of

Further, it is desirable that the light source is a fluorescent lamp and the spectral characteristic level thereof is set to be lower in the order of blue, green and red.

The charge coupled device is preferably a color charge coupled device.

Further, a document reading device according to the present invention has the optical device according to claim 1.

[0015]

In the optical device of the present invention having the above structure, the spectral characteristic of the light source has a spectral characteristic contradictory to the spectral sensitivity characteristic of the charge-coupled device. Output intensity becomes constant.

Further, since the document reading device according to the present invention has the optical device according to the first aspect of the present invention, the spectral sensitivity correction circuit is not required, and the cost can be reduced.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the optical device according to the present invention. In FIG. 1, a fluorescent lamp 11 as a light source elongated in the depth direction is formed in a gutter-shaped cross section and has a thin film of aluminum vapor-deposited on its inner surface in order to efficiently irradiate the original 12 with the emitted light in a specific direction. It is arranged at the focal position of the reflecting mirror 13.

Metal terminals (not shown) are fixed to both ends of the fluorescent lamp 11, and the DC power supply 14 is connected to the metal terminals.
When the current is supplied from the fluorescent lamp 11, the fluorescent lamp 11 is turned on and emits light. The emitted radiated light is reflected by the reflecting mirror 13, passes through the original document supporting member 15 formed of glass or the like, and is then applied to the original document 12.

The reflected light reflected by the original 12 is focused by the rod lens array 16 and then
The light enters the color CCD (charge coupled device) 17 and is converted into a minute voltage value as an electric signal. The converted voltage is amplified by the amplifier circuit 18 and then amplified by the signal processing circuit 19
Is output to. The signal processing circuit 19 processes the red (R), green (G), and blue (B) signals output from the color CCD 17 to reproduce a color image.

By the way, in this embodiment, the spectral characteristic of the fluorescent lamp 11 has a property contradictory to the spectral sensitivity characteristic of the color CCD 17. Specifically, as can be seen from the spectral sensitivity characteristic of the color CCD shown in FIG. Have different sensitivities in the order of red (R)> green (G)> blue (B), the spectral characteristic levels are blue (B)> green (G)> red (R) as shown in FIG.
The fluorescent lamp 11 set in this order is used as a light source.

To set the spectral characteristic levels of the fluorescent lamp 11 in the order of blue (B)> green (G)> red (R), the fluorescent lamp 1
This is performed by changing the compounding ratio of the phosphor of No. 1. That is, in general, among the components of the phosphor, the composition of blue (B) is (SrCaBaMg) ₅ (PO ₄ ) ₃ Cl, the composition of green (G) is LaPO ₄ , and the composition of red (R) is Y ₂ O
₄ is general, and is performed by changing these weight ratios.

Next, the operation of this embodiment will be described.

In this embodiment, the spectral characteristic levels of the fluorescent lamp 11 are set in the order of blue (B)> green (G)> red (R), so that the output intensity of the color CCD 17 is blue (as shown in FIG. 3). B), green (G), and red (R) are almost the same. This eliminates the need for optical filters.

The optical device of this embodiment can be applied to a document reading device such as a color copying machine or a facsimile device. And when applied to a color copier,
Since the output intensity of the color CCD 17 of this embodiment is almost the same, a clear image can be obtained.

[0026]

As described above, according to the optical device of the present invention, a charge-coupled device for electrically converting light,
Since the light source having a spectral characteristic that is contrary to the spectral sensitivity characteristic of the charge-coupled device is provided, the output intensity from the charge-coupled device becomes constant even when no filter is used. As a result, the number of parts can be reduced, and an inexpensive optical device can be provided.

Further, according to the document reading apparatus of the present invention, by having the above-mentioned optical device, the correction circuit of the spectral sensitivity becomes unnecessary and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an optical device according to the present invention.

FIG. 2 is a spectral distribution diagram of a fluorescent lamp in the optical device of FIG.

FIG. 3 is a diagram showing an output of a color CCD in the optical device of FIG.

FIG. 4 is a schematic configuration diagram showing a conventional optical device.

FIG. 5 is a spectral distribution diagram of the halogen bulb shown in FIG.

FIG. 6 is a diagram showing a spectral sensitivity characteristic of a color CCD.

7 is a diagram showing the output of a color CCD in the optical device of FIG.

[Explanation of symbols]

 11 Fluorescent Lamp (Light Source) 12 Document 13 Reflector 14 DC Power Supply 15 Document Support Member 16 Rod Lens Array 17 Color CCD (Charge Coupled Device) 18 Amplification Circuit 19 Signal Processing Circuit

Claims (5)

[Claims] 1. An optical device comprising: a charge-coupled device for converting light into an electrical signal; and a light source having a spectral characteristic that is contrary to the spectral sensitivity characteristic of the charge-coupled device. 2. The optical device according to claim 1, wherein the light source is a fluorescent lamp. 3. The light source has a spectral characteristic level of blue,
The optical device according to claim 1 or 2, wherein the green and red are set to be lower in that order. 4. The optical device according to claim 1, wherein the charge-coupled device is a color charge-coupled device. 5. An original reading device comprising the optical device according to claim 1.