JP2001052107A - Optical surface displacement detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical surface displacement detector and a turn recognizing device. SOLUTION: This device has a line light source (light source) 101 for irradiating the surface of an object 107 to be inspected, with which at least one of projecting part (having an almost fixed height) and recessed part (having almost fixed depth) is formed on the surface, with light, one cylindrical lens (optical element) 111 for unidirectionally condensing reflected light on the surface of the object 107 to be inspected into linear light and plural photodetectors (PSD) 115 having photodetecting planes to which the linear light is made incident, providing the photodetecting planes at positions almost conjugate with the surface of the said object to be inspected and divided in the line direction of the said linear light and it is one-dimensionally detected by the outputs of the respective PSD 115 which one of plane part, projecting part and recessed part is on the surface of the confronted object 107 to be inspected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical surface displacement detecting device for detecting a concave portion or a convex portion on the surface of a test object.

[0002]

2. Description of the Related Art As an example of an optical surface displacement detecting device,
There is a configuration shown in FIG. In the figure, the line light source 3 irradiates the card 1 conveyed in the direction of the arrow and embossed with broad light.

When the card 1 is irradiated with light, as shown in FIG. 11, a shadow of the projection of the emboss 1a is formed on the card 1.
G occurs. The shadow G is read by a line sensor 5 via a rod lens array 4 including a plurality of lenses as a condenser lens.

[0004]

However, in the optical surface displacement detecting device having the above-mentioned structure, the dispersion of the performance of each lens of the rod lens array 4 becomes the difference of the spot state on the line sensor 5 and the read signal varies. There is a problem that occurs.

Further, since the rod lens array 4 is used, there is a problem that the cost is increased. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to provide an optical surface displacement detection device having less variation in a read signal.

A second object is to provide a low-cost optical surface displacement detecting device.

[0007]

According to a first aspect of the present invention, there is provided an apparatus for irradiating light to a surface of a test object having a flat portion and at least one of a convex portion and a concave portion. A light source, an optical element for converging light reflected on the surface of the test object in one direction and forming linear light, and a light receiving surface on which the linear light is incident, wherein the light receiving surface is a surface of the test object And a plurality of light receiving elements divided in the linear direction of the linear light are provided at positions substantially conjugate to each other, and the output of each light receiving element causes the surface of the test object to have a flat surface / projection / An optical surface displacement detecting device for detecting whether any of the concave portions is present.

As an optical element which condenses reflected light on the surface of the test object in one direction to form linear light, a cylindrical lens,
Although there are a Grin lens, a hologram, a diffraction grating, and the like, these optical elements can be realized as one (single) optical element (lens).

As described above, when the optical element which condenses the reflected light on the surface of the test object in one direction and converts it into linear light is used, compared with the case where a rod lens array including a plurality of lenses is used, Variations in the read signal are reduced.

[0010] Further, the present invention can be realized at low cost as compared with the case where a rod lens array including a plurality of lenses is used. It is preferable to shorten the focal length of the optical element from the viewpoint that the amount of flare in the linear direction of the linear light on the light receiving surface of the light receiving element is reduced.

The phrase "any one of a flat portion / a convex portion / a concave portion" includes "any one of a flat portion / a convex portion" and "any one of a flat portion / a concave portion". According to a second aspect of the present invention, at least one of the test object and the light source according to the first aspect of the invention is moved in a direction intersecting a line direction of the linear light, and an output of each of the light receiving elements is provided. An optical surface displacement detection device for detecting the surface of a test object two-dimensionally.

At least one of the test object and the light source is moved in a direction intersecting the line direction of the linear light, and a two-dimensional displacement of the test object surface is detected based on an output of each of the light receiving elements. By doing so, for example, it is possible to recognize a character formed by a convex portion or a concave portion by embossing or the like formed on the card surface.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, light emitted from a line light source 101 as a light source is irradiated on a test object 107 having a flat surface portion 107a and an embossed convex portion 107b formed on the surface.

As shown in FIG. 2, the surface of the test object 107 has an embossed convex portion 107 formed on a flat portion 107a.
b indicates the character (the number 4 in this embodiment)
Are formed.

Returning to FIG. 1, light reflected on the surface of the test object 107 is converged in one direction by a cylindrical lens 111 having a short focal length, and is received by a light receiving surface 115a of a semiconductor position detecting element (hereinafter referred to as PSD) 115. The top is irradiated with linear light.

The surface of the test object 107 and the light receiving surface of the PSD 115 are arranged so as to have a conjugate positional relationship. The test object 107 is moved by a scanning unit (not shown) in a direction intersecting the line direction of the linear light (the direction of arrow I in the figure).

As shown in FIG. 3, n PSDs 115 are provided in the linear direction of the linear light. Next, referring to FIG.
The electrical configuration of the present embodiment will be described. In the figure,
121 is an amplifier for amplifying the analog signal of the PSD 115,
Reference numeral 123 denotes a binarization circuit for binarizing the amplified analog signal, and reference numeral 125 denotes a character discrimination circuit for comparing the binarized signal with the character pattern table 127 to discriminate a character.

Next, the operation of the above configuration will be described. As shown in FIG. 5, the light reflected by the flat portion 107a of the test object 107 reaches A 'on the light receiving surface 115a of the PSD 115, and the light reflected by the convex portion 107b of the emboss reaches B' of the PSD 115.
The light receiving position is different, and the output of the PSD 115 is different depending on the light receiving position.

For this reason, the displacement distribution in the height direction of the surface of the test object 107 can be detected one-dimensionally, and the test object 10 can be detected.
1, the displacement distribution in the height direction of the surface of the test object 107 can be detected two-dimensionally.

That is, the analog output from the PSD 115 is
The signal is amplified by the amplifier 121 and binarized by the binarization circuit 123. The character determination circuit 125 compares the binarized signal with the character pattern table 127,
Read characters.

According to the above configuration, the rod lens array composed of a plurality of lenses is used by using the cylindrical lens 111 which condenses the reflected light on the surface of the test object 107 in one direction and converts it into linear light. As compared with the case, the variation of the read signal is reduced. Also, the cost is lower than in the case where a rod lens array is used. Further, the test object 1
As shown in FIG. 6, the light that has hit the surface of 07 is condensed by the cylindrical lens 111 in the Y direction, but is not condensed in the X direction.

Therefore, as shown in FIG.
The light beam diffused at the position Xi on the surface of
Not only at position X'i at position 15, but also at X'i + 1 and X'i-1
To reach.

The light reaching the X'i + 1 and X'i-1 portions appears on the PSD 115 as a flare F in the linear direction (X 'direction) of the linear light as shown in FIG. . The amount of the flare F increases as the distance between the cylindrical lens 111 and the light receiving surface of the PSD 115 increases.

Therefore, in the present embodiment, by shortening the focal length of the cylindrical lens 111, the distance between the cylindrical lens 111 and the light receiving surface of the PSD 115 is shortened, the amount of flare F generated is reduced, and the PSD 11
5 is preferable because the signal from 5 is not disturbed and the accuracy of character determination is improved.

The present invention is not limited to the above embodiment. In the above embodiment, the test object 107
Has a flat portion 107a and an embossed convex portion 107b.
However, even with a test object having a flat portion and an embossed concave portion, and a flat portion, a test object having a convex and concave embossed portion, the output of the PSD 115 is different.
Applicable.

Further, the protrusions or recesses may be other than the protrusions or recesses of the emboss. Further, instead of the PSD 115, n × m (m is a direction intersecting the line direction of the linear light)
An integer greater than or equal to 1 and n is the direction along the line direction of the linear light, 2
An array of PDs (photodiodes) divided into the above integers) can also be used. For example, as shown in FIG.
A divided array PD 225 may be used.

Further, in the above embodiment, the test object 107 is moved in the direction of arrow I in FIG. 1, but the line light source 101, the cylindrical lens 111, the PSD 115
May be moved in the direction of arrow I.

In the above-described embodiment, the line light source 101 is used as a light source for irradiating linear light to the surface of the test object. However, various light sources are used in the optical path from the light source to the test object. An optical element (including a filter or the like) that converts light from a light source into linear light may be provided, and the test object may be irradiated with linear light.

[0029]

As described above, according to the first aspect of the present invention, a plurality of lenses can be obtained by using an optical element which condenses reflected light on the surface of a test object in one direction and converts it into linear light. As compared with the case of using a rod lens array composed of :, it is possible to obtain a low-cost optical surface deviation detecting device while reducing the variation of the read signal.

According to the second aspect of the present invention, at least one of the test object and the light source is moved in a direction intersecting the line direction of the linear light, and at least one of the test object and the light source is moved. Is moved in a direction intersecting the line direction of the linear light, and by detecting the two-dimensional displacement of the surface of the test object by the output of each light receiving element, for example, an emboss formed on the card surface Character recognition such as

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment.

FIG. 2 is a diagram illustrating a surface of a test object in FIG. 1;

FIG. 3 is a diagram illustrating a light receiving surface of the PSD of FIG. 1;

FIG. 4 is a diagram illustrating an electrical configuration of the embodiment.

FIG. 5 is a diagram illustrating the operation of FIG.

FIG. 6 is a view for explaining the light collecting direction of the cylindrical lens of FIG.

FIG. 7 is a diagram illustrating flare.

FIG. 8 is a diagram illustrating a flare.

FIG. 9 is a diagram for explaining another embodiment.

FIG. 10 is a diagram illustrating a conventional optical surface displacement device.

FIG. 11 is a diagram illustrating the operation of FIG.

[Explanation of symbols]

 101 line light source (light source) 111 cylindrical lens 107 test object 115 PSD (light receiving element)

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Nobuyuki Baba 920 Ninomiya, Misaka-cho, Higashi-Yatsushiro-gun, Yamanashi F-term (reference) 5B029 AA05 BB02 BB04 BB05 CC06 5B072 AA00 CC26 DD02 LL09 LL19

Claims (2)

[Claims] A light source for irradiating light to a surface of the test object having a flat surface and at least one of a convex portion and a concave portion; An optical element that emits light and has a light receiving surface on which the linear light is incident. The light receiving surface is provided at a position substantially conjugate with the surface of the test object, and is provided in a linear direction of the linear light. A plurality of divided light receiving elements, and the output of each light receiving element causes the surface of the test object to have a planar portion
An optical surface displacement detection device, which detects whether it is one of a convex portion and a concave portion. 2. The method according to claim 2, wherein at least one of the test object and the light source is moved in a direction intersecting a line direction of the linear light, and the output of each of the light receiving elements causes the surface of the test object to be two-dimensionally moved. 2. The optical surface displacement detecting device according to claim 1, wherein the optical surface displacement is detected by the following method.