JPH02276913A - Recorder equipped with optical pen position detecting mechanism - Google Patents

Abstract

PURPOSE:To improve the reliability of a recorder and to improve the position detection accuracy by using the optical pen position detecting mechanism for the recorder. CONSTITUTION:The output light from a light emitting element 21 is branched by a half-mirror 22, one light component is reflected by a reference mirror 23, and the other light component is a mirror 24 which is fixed to a pen supporting part 11 and moves together with a pen 12. Those reflected light components are multiplexed by the mirror 22 and made incident on a photodiode 25. Here, when the mirrors 23 and 24 are at an equal distance from the mirror 22, both the light beams with any wavelength intensify each other, but when the mirror 24 is moved by X/2 in parallel, an optical path difference X is generated and light beams satisfying X=nlambda (n = integer lambda: wavelength) intensify each other, so that light fringes appear. Light beam satisfying X(n+1/2)lambda (integer lambda: wavelength) cancel each other to form dark fringes, thereby obtaining interference fringes corresponding to the optical path difference. For the purpose, a reference position is determined in advance to detect the position of the mirror 24 from a movement distance DELTAZ.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement in a pen position detection mechanism of a recorder.

<Conventional technology> Conventionally, the pen position detection R side of a recorder uses a resistance potentiometer to detect the brush position of a flat resistor, a magnetostrictive potentiometer to detect the propagation time of ultrasonic waves to the detection position, etc. location has been detected.

<Problems to be Solved by the Invention> However, recorders equipped with a pen position detection mechanism using a resistance potentiometer have a contact part that detects the brush position of the sliding resistance, so there is a problem in terms of reliability. In addition, recorders equipped with a pen position detection mechanism using a magnetostrictive potentiometer do not have a contact part, which improves reliability, but the mechanism is complicated and the device is expensive. There was a problem.

The present invention has been made based on the above-mentioned problems of the prior art, and by adopting an optical structure for the pen position detection mechanism, an optical pen with a simple structure, high reliability, high resolution, and low cost is provided. The purpose of this invention is to provide a recorder equipped with a position detection mechanism.

<Means for Solving the Problems> The configuration of the present invention for solving the above problems is to divide the output light of the light emitting element by a half mirror, and divide the output light from the reference mirror and the mirror fixed to the pen support part into reflected light. The pen position is detected from the interference fringe pattern proportional to the optical path difference obtained by interfering with the pen.
Further, the present invention is characterized by having a structure in which a light emitting element fixed to the pen or a pen support part and a photodiode position detector having a high resistance layer on the surface are provided, and the light emitting element and the light emitting element are It is characterized by the provision of a mirror fixed to the pen support with its normal direction inclined to the element, and a photodiode position detector having a high resistance layer on its surface.

<Function> In this way, by making the pen position detection R1b of the recorder optical, the principle and am are simple and non-contact type, so reliability is increased, and detection is also possible by using interference. Sensitivity is high, and therefore position detection accuracy can be made highly precise.
In addition, the configuration can be made simpler by providing a light emitting element and a photodiode position detector, and the mirror fixed to the pen support part is tilted in the normal direction with respect to the light emitting element. By providing a configuration in which a large photodiode position detector that covers the entire movable range of the pen is not required, the configuration can be further simplified.

<Example> Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a block diagram showing an embodiment of a recorder equipped with an optical pen position detection mechanism according to the present invention.

In FIG. 1, 1 is the recorder main body, 11 is a pen support part,
12 is a pen fixed to the pen support 11, 13 is a recording paper, and 20 is an optical position detection mechanism.

The optical position detection 111m20 is configured using a Michelson interferometer, and includes a light emitting element 21 fixed to the recorder body 10, a half mirror 22, a reference mirror 23, a photodiode 25, and a pen fixed to the pen support 11. It consists of a mirror 24 that moves together with 12.

In such a configuration, the output light from the light emitting element 21 is split into two by the half mirror 22, one light is fixed to the reference mirror 23, and the other light is fixed to the pen support 11, and the light is fixed to the pen 1.
The light is reflected by a mirror 24 that moves along with the movement of the light beam 2. These respective reflected lights are combined by a half mirror 22 and input to a photodiode 25. Here, if they are at the same distance from the reference mirror 23, mirror 24, or half mirror 22, both light beams will strengthen each other for light of all wavelengths, but if one mirror 24 is moved in parallel by x/2, the optical path of There is a difference, x=
Light that satisfies nλ (n; an integer) strengthens each other, and in this case four pairs appear, and light that satisfies x = (n + 1/2) λ (n; an integer) cancel each other out, making it clear at this time. Fringe will appear, indicating interference fringes depending on the optical path difference. As the optical path difference is further changed, the interference fringes occurring on the photodiode 25 move. Here, if the number of interference fringes (bright and dark pattern) passing through any one point on the photodiode 25 is M, the moving distance Δ2 of the mirror 24 is expressed by the following equation.

△z=M・λ/ 2 n...■ Note that n: refractive index of air λ: wavelength. Therefore, by determining the reference position in advance, it is possible to adjust the moving distance from Z to the mirror 24. Position can be detected. In other words, the position of the pen ]2 moving on the recording paper 13 is
Photodiode 1 (Fl on 25: interference fringes corresponding to the optical path difference between the reference mirror 23 detected at one point and the mirror 24 that moves with the movement of the pen 12 fixed to the pen support 11) The number M is detected, and from the above equation 0, mirror 2
4, the moving distance ^1ΔZ, that is, the position of the pen 12 fixed to the pen support portion 11 can be detected.

Note that the configuration of the interferometer is not limited to the Michelson interferometer using the mirror shown above, but may be any configuration that allows two lights branched by the interferometer to interfere.

FIG. 2(a) shows the optical pen position detection system according to the present invention.
FIG. 2 is a block diagram showing an embodiment of a recorder according to claim 2, and FIG. FIG. 3 is a detailed diagram showing the positional relationship. In FIG. 2, the same elements as those in FIG. 1 are given the same reference numerals and redundant explanations will be omitted.

In FIG. 2(a), reference numeral 20- is an optical position detection mechanism, and the pen 12 is composed of a light emitting cord 21 fixed to the pen support 11 and a PSD 30 having a high resistance layer on its surface. This PSD 30 includes a high-resistance layer 31 having a resistance value proportional to the length, and a high-resistance layer 31 having a resistance value proportional to the length.
Electricity ff extracted from both ends of 1! It is composed of A, B, and a common electrode. In such a configuration, the distance from the electrode A to the light emitting element 21 is X, and its resistance is Rx.
, the distance between the terminals #lAB is L, and its resistance is R[,
Photocurrent due to output light from the light emitting element 21 ■0 is electrode A,
B, and its fIiI^ and IB are expressed by the following equation.

I^=IO(RL -RX)/RL IB =IO・RX/RL Here, assuming that the resistance layer is uniform and the resistance is proportional to the length, I^=IO, (1, -X)/ L IB=IO-X/L That is, if the ratio of IA and rB is the position signal P, then P=I8/toB-(L-X)/L=L/X-1...■ .

Furthermore, the ratio of the difference and the sum of IA and IB may be used as the position signal P, in which case, P''= (TA-IB)/(I^1IB)= (L-
2X)/L=1-2X/L...■, 0 formula or 0
From the equation, a position signal unrelated to fluctuations in light intensity can be obtained, and the position of the pen 12 can be detected.

FIG. 3 is a block diagram showing an embodiment of a recorder equipped with an optical pen position detection mechanism according to the present invention. In FIG. 3, the same elements as those in FIGS. 1 and 2 are designated by the same reference numerals, and redundant explanations will be omitted.

FIG. 3 shows a configuration in which reflected light from a mirror 26 whose normal direction is inclined by θ with respect to the light emitting element 21 is incident on the PSD 30, and the pen support 11 (pen 12) is moved by a distance ilL. Then, the reflected light from mirror 41 becomes PS
It will move by (L - tan2θ) on D30. Therefore, compared to the configuration shown in FIG. 2, there is no need for a large PSD 30 that covers the entire movable range of the pen 12, and the configuration can be simplified.

<Effects of the Invention> As specifically explained above in conjunction with the embodiments, according to the present invention, the pen position detection mechanism of the recorder is an optical type, which is a non-contact type, thereby improving the reliability of the device. It can be made higher,
By using interference, detection sensitivity can be increased and position detection accuracy can be increased. In addition, since the detector only needs to measure the brightness and darkness of light at any one point in space, an inexpensive photodiode can be used, and the detection amount is the number of moving interference fringes, so it is easy to scan and record. Furthermore, the position resolution of the photodiode is 10 μr.
It has a sufficiently high resolution as a position detection element of a recorder. Therefore, it is possible to realize a recorder with a highly reliable, high resolution, and inexpensive optical pen position detection mechanism.
In addition, the configuration of claim 2 allows the configuration to be made simpler, and the configuration of claim 3 eliminates the need for a large photodiode position detector that covers the entire movable range of the pen. It is possible to realize a recorder equipped with an optical pen position detection mechanism with a simplified configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of a recorder equipped with an optical pen position detection mechanism according to the present invention, and FIGS. 2 and 3 are block diagrams showing other embodiments of the present invention. 10...Recorder body, 11...Pen support section, 12.
...Pen, 13...Recording paper, 20.20-...Optical position detection mechanism, 21...Light emitting element, 22...Half mirror 23...Reference mirror, 24.26... Mirror 25... Photodiode, 30... Photodiode position detector, 31... High resistance layer. (B)

Claims (3)

[Claims] (1) The output light of the light emitting element is divided by a half mirror,
An optical pen position detection mechanism characterized in that the pen position is detected from an interference fringe pattern proportional to an optical path difference obtained by interfering reflected light from a reference mirror and a mirror fixed to a pen support. Recorder with. (2) A recorder equipped with an optical pen position detection mechanism characterized by having a structure in which a light emitting element is fixed to a pen or a pen support, and a photodiode position detector having a high resistance layer on the surface. . (3) An optical system comprising a light emitting element, a mirror fixed to the pen support with its normal direction inclined to the light emitting element, and a photodiode position detector having a high resistance layer on its surface. A recorder equipped with a pen position detection mechanism.