JPH04100478A - Shading correcting plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is designed to measure the intensity of light incident on a photoelectric conversion element when a light source illuminates an original and the transmitted light transmitted through the original is read by a photoelectric conversion element. The present invention relates to a shading correction plate that corrects for averaging.

[Conventional technology]

For example, when reading an image original such as a film original into a computer, conventionally, as shown in FIG.
An illumination lens 3 disposed along the optical axis 2 of the illumination lens 3, an imaging lens 4 disposed behind the illumination lens 3, and an optical reading element for reading the optical image formed by the imaging lens 4. The film original 6 is inserted between the illumination lens 3 and the imaging lens 4, and the image formed on the film original 6 is basically composed of a CCD sensor array (hereinafter simply referred to as CCD) 5. Information is read by CCD 5. However, the light source 1, such as a halogen lamp, has a filament at the center of the lamp, and is structured to irradiate light by emitting light from the filament. Naturally, deviations occur. Therefore, even if the light is focused by the illumination lens 3 and illuminated on the film original 6, a deviation will naturally occur in the light that has passed through the illuminated film original 6, that is, the light that is focused by the imaging lens 4. ing. If a deviation occurs in the light condensed by the imaging lens 4 in this way, a deviation also occurs in the light incident on the CCD 5, and naturally, a deviation also occurs in the output of the CCD 5.

If there is a deviation in the output of the CCD 5, the image cannot be read accurately, so a fourth
As shown in the figure, a shading correction plate 7 having curved portions at both ends is provided via an adjustment screw 8. This shading correction plate 7 can be removed by loosening the screw 8.
By moving in the direction perpendicular to the line of D5 (direction of arrow A), light entering the CCD 5 is blocked, and the CCD
The amount of light incident on the CCD 5 is adjusted from the center to both ends of the CCD 5 so that the output from the CCD 5 is uniform.

[Problems to be Solved by the Invention] By the way, when adjusting the amount of light incident on the CCD 5 using the shading correction plate 7 as described above, it is necessary to loosen the adjustment screw 8 and measure the output from the CCD 5 before adjusting the shading correction plate 7. Stop.

Fix with adjustment screw 8. In this way, all adjustments of the shading correction plate 7 were performed manually.

Therefore, depending on how the 5 adjustment screws 8 are tightened, the fixed position of the shading correction plate may shift to the IID direction, resulting in C
Since the output of the CD5 also changes, careful adjustment work is required, resulting in extremely low work efficiency.

In addition, although there are multiple elements (sensors) that make up the CCD 5, the shading correction plate 7 is set to correct only one edge portion, so it can handle deviations in the output characteristics of each sensor 9 of the CCD 5. This made the shading correction work even more difficult and less accurate.

This invention was made in view of this technical background, and its purpose is to simplify adjustment work, have excellent work efficiency, and
Another object of the present invention is to provide a shading correction plate capable of performing highly accurate shading correction.

[Means to solve the problem]

In order to achieve the above object, the structural features of this invention are as follows:
The amount of light incident on the photoelectric conversion element, which is arranged on the @ plane in the light incident direction of the photoelectric conversion element used in the image reading device, is
In a shading correction plate that corrects the optical path of light by partially blocking it, the correction plate includes a plurality of thin column-shaped light blocking members capable of blocking light passing through the optical path at minute portions;
The light shielding members are arranged in parallel in a direction substantially perpendicular to the optical path of the incident light and the photoelectric conversion element array, and support members support the light shielding members so that they can move forward and backward from the direction perpendicular to the optical path and the photoelectric conversion element array. It's because it's configured.

[For production]

According to the above configuration, the amount of light incident on the photoelectric conversion element from the front surface of the photoelectric conversion element is increased by moving each light shielding member forward and backward with respect to the optical path, so that the amount of light that is blocked by each light shielding member is Wl.
I will be treated. Therefore, when adjusting, the output level can be easily made flat by advancing and retracting each light shielding member in sequence without looking at the output of the photoelectric conversion element.

〔Example〕

FIG. 1 is a front view showing the relationship between a shading correction plate and a CCD according to an embodiment. The image reading device itself using this shading correction plate is equivalent to the one shown in FIG. Explanation will be omitted.

Referring also to the perspective view of FIG. 2, the shading correction plate 11 includes light shielding members 12 made up of a plurality of small-diameter columnar members, and the light shielding member 12, as shown in the perspective view of FIG. The light shielding members 12 are arranged in parallel and each light shielding member 12 is supported so as to be movable independently. In this embodiment, the tip 14 of the light shielding member 12 is rounded, and the support structure of the support member 13 utilizes frictional force.

As shown in FIG. 1, the shading correction plate 11 is arranged so that the longitudinal direction of the light shielding member 12 is substantially perpendicular to the line of the CCD 5, and so that its tip 14 can cover the front surface of the CCD 5. be done.

Then, the tip 14 is once aligned in a predetermined line, for example, at a position that covers the entire front surface of the CCD 5, and the light shielding member 12 is retreated without measuring the output of the CCD 5. In this way, the output of the CCD 5 is adjusted to be flat without moving each light shielding member 12. After the adjustment is completed, each light shielding member 12 is fixed, preferably by fixing means such as adhesive.
is fixed to the support member 11. FIG. 1 shows this state.

In this way, the tip 14 of each light shielding member 12 is uneven with respect to the front surface of the CCD 5, and the amount of light shielding can be easily and reliably adjusted in small areas. In this way, the light shielding member 12
If the light is blocked in minute parts by a thin columnar member and the amount of light blocked can be adjusted, not only shading correction due to the deviation of the emitted light from light source 1 but also correction of the output characteristics of each sensor of CCD 5 will be performed at the same time, resulting in shading correction. Electrical correction performed in addition to mechanical correction by the plate 11 is also simplified.

Note that the diameter and power of the light shielding member 12 and the support structure of the support member are appropriately selected depending on the number of sensors 9 of the CCD 5, the intended use, required precision, and the like.

〔Effect of the invention〕

As explained above, according to the present invention, a plurality of thin columnar light shielding members capable of blocking light passing through an optical path at minute portions;
The light shielding members are arranged in parallel in a direction substantially perpendicular to the optical path of the incident light and the photoelectric conversion element array, and support members support the light shielding members so that they can move forward and backward from the direction perpendicular to the optical path and the photoelectric conversion element array. With this configuration, it is possible to easily correct the output characteristics of the photoelectric conversion element array to be flat simply by advancing and retracting each light shielding member. At this time, correction is performed over minute portions of the optical path, and deviations of each photoelectric conversion element itself are also corrected, making it possible to perform highly accurate shading correction.

[Brief explanation of drawings]

Fig. 1 is a front view showing the relationship between the shading correction plate and the photoelectric variable sensor f row according to the embodiment, Fig. 2 is a perspective view of the main parts of the shading correction plate, and Fig. 3 is a schematic configuration diagram of the image reading device. , FIG. 4 is a front view of a conventional shading correction plate. In the figure, 1 is a light source, 5 is a CCD (photoelectric conversion element), 11 is a shading correction plate, 12 is a light shielding member, 13 is a support member, and 14 is a tip (of the light shielding member). Patent applicant: Fujitsu General Co., Ltd.

Claims (1)

[Claims] (1) Shading correction, which is disposed in front of a photoelectric conversion element used in an image reading device in the light incident direction, and corrects the amount of light incident on the photoelectric conversion element by partially blocking the optical path of the light. In the plate, a plurality of thin column-shaped light shielding members capable of blocking light passing through the optical path with minute parts, and each of the light shielding members are arranged in parallel in a direction substantially perpendicular to the optical path of the incident light and the photoelectric conversion element array,
A shading correction plate characterized by comprising a support member that supports the optical path and the photoelectric conversion element array so as to be freely advanced and retracted in a direction perpendicular to the optical path and the photoelectric conversion element array.