JPS60242325A - Color sorting device - Google Patents

Abstract

PURPOSE:To improve the ability in color sorting by arranging a photodiode as a photodetecting element behind a slit plate and the focusing point of reflected light, and photodetecting the reflected light to area wider than a photodetection area sectioned with a slit. CONSTITUTION:When the photodetecting element 9 photodetects the reflected light 4 from rice grains 3, etc., irradiated with illumination light 2 from a lamp 1 for the sorting of the rice grains, etc., the photodiode used as the element 9 is arranged behind the slit plate 7 and also distance l behind the focus F of reflected light 4. Consequently, the wide photodetection area A2 on the photodetection surface 10 of the element 9 is obtained exceeding the photodetection area 11 sectioned with the slit 8 of a plate 7, so even variance in photodetection sensitivity on the photodetection surface is absorbed even when there is the variance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color sorting method for sorting rice grains and other grains.

Conventional ■Many methods have been proposed for narrowing color sorting methods, but the basic technology is to flow the grains to be sorted in an aligned stream, and to shine light from a lamp onto this aligned stream to detect its reflection. Light passes through a condensing lens, filter, and slit plate and is received by a light receiving element. If reflected light with an amount of light different from the standard color is received, the particles to be sorted that emitted the reflected light are determined to be defective, and the particles The grains to be sorted that are determined to be defective by the ejector are excluded from the alignment method, and a conventional example of how to use such a condensing lens, filter, slit plate, and light receiving element is disclosed in Japanese Patent Application Laid-Open No. 57-1999. No. 3 of Publication No. 187628
There is a method disclosed in the figure.

The principle of this method is as shown in FIGS. 3 and 4 of the attached drawings of this specification.
hits the rice grain 3, becomes reflected light 4, passes through the condenser lens 5 and filter 6, and is received by the light receiving area 11 defined in advance on the light receiving surface 10 of the light receiving element 9 by the slit 8 of the slit plate 7. . This light receiving area is shown as A1 in the figure. The surface and slit 8 are for blocking much of the reflected light from the rice grains 3a other than the rice grain 3, and by receiving only the necessary reflected light 4 in the light receiving area 11, the resolution for each rice grain is increased. It is something that exists.

However, when a photodiode is used as the light-receiving element 9, the light-receiving sensitivity of the light-receiving surface 10 is not necessarily uniform. If it is lower than the other parts, the color sorting performance will be lowered.

(b) In order to improve the configuration, in the color selection method according to the present invention, a photodiode is arranged behind the slit plate and behind the focal point of the reflected light,
The reflected light is received over a wide area outside the light receiving area defined by the slit.

The reflected light from the rice grains is focused by the condensing lens, and only the reflected light that passes through the slit of the slit plate and focuses is received by the photodiode. Unlike the conventional method, the light is placed behind the slit plate and behind the focal point of the reflected light, so conventionally the light would be received only within the light receiving area defined by the slit on the light receiving surface, but in the present invention, the light is received only within the light receiving area defined by the slit on the light receiving surface. The reflected light is received over a wide area. Therefore, unnecessary reflected light is blocked by the slit, and only necessary reflected light is received by the light receiving surface of the photodiode over a relatively wide area.

An embodiment of the color selection method according to the present invention will be described with reference to FIGS. 1 and 2. Incidentally, parts common to the conventional one are designated by the same reference numerals and redundant explanation will be omitted.

A photodiode is used as the light receiving element 9, and this photodiode is located behind the slit plate 7 and receives the reflected light 4.
is placed at a distance l behind the focal point F of . Therefore, although there is a light-receiving area 11 defined by the slit 8 on the light-receiving surface 10 of the photodiode, since the photodiode is located behind the focal point F, the reflected light 4 is reflected by the wider light-receiving area A2 extending outside the light-receiving area 11. will receive light. As a result, if the light receiving surface 10 of the photodiode
Even if there are variations in the light-receiving sensitivity, since the light is received in the wide light-receiving area A2, the variation in the light-receiving sensitivity is absorbed, and if the reflected light 4 has a different amount of light than the reference color, it can be reliably detected.

(c) Effect Since the color selection method according to the present invention has the content as explained above, although unnecessary reflected light is cut off by the slit, there is no possibility that the area outside the light-receiving area defined by the slit will be absorbed. Since the reflected light is received over a wide area, even if there are variations in the light-receiving sensitivity of the photodiode used as the light-receiving element, the reflected light will be reliably received regardless of the variations, and the amount of light different from the reference color will be detected. If it is reflected light, it is possible to distinguish between yellows, and it is possible to perform highly accurate color selection that is not affected by variations in the light receiving sensitivity of the photodiodes.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram of an optical system used in the method of the present invention. Fig. 2 is a front view showing the light receiving surface of a photodiode. Fig. 3 is a schematic explanatory diagram of an optical system equivalent to Fig. 1 showing a conventional example. FIG. 4 is a front view showing the light-receiving surface corresponding to FIG. 2. 1 ---------- Lamp 2 -------1 Irradiated light 3.3 a --------m-Rice grain 4 ---------- Reflected light 5 ------- -1 Condensing lens 6 -1111・-Filter 7 ----------- Slit plate 9 ----------1 Light receiving element 10 -1 Light receiving surface 11 ------- Light receiving area A1, A2 -1------ Light receiving area

Claims (1)

[Claims] Grains to be sorted are made into an aligned stream, and the aligned stream is irradiated with light from a lamp, and the reflected light is passed through a condenser lens, a filter, and a slit plate, and is received by a light-receiving element. In the color sorting method, in which grains to be sorted that emit the reflected light are classified as defective when the reflected light is received, a photodiode is used as the light-receiving element, and this photodiode is placed behind the slint plate and in the direction of the reflected light. A color selection method that is arranged behind a focal point and receives reflected light over a wide area outside the light receiving area defined on the light receiving surface of a photodiode by a slit of a slit plate.