JPH0255853B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pick-up needle that extracts an information signal from a recording medium by scanning relative to the recording medium, and a detection section that detects the information signal as a change in capacitance. This invention relates to a capacitive playback device having a pick-up support structure for holding a pick-up needle.

Conventional Structure and Problems Currently, video disk playback devices that detect information signals as changes in capacitance are equipped with an oscillator between a pickup needle and a recording medium (hereinafter referred to as a video disk). The output signal from the oscillator is applied to a resonant circuit including a reactance circuit formed in the oscillator to output a signal with a resonant frequency component determined by the reactance etc., and the carrier wave is modulated according to the level of the signal of the resonant frequency component. The configuration is such that an information signal can be obtained by

In the above-mentioned devices, the resonant frequency of the resonant circuits usually varies because the mounting positional relationship between the detection section including the resonant circuit and the pick-up needle on the housing is not uniform.

A conventional playback device will be described below with reference to the drawings. FIG. 1 shows an embodiment of a conventional playback device, in which 1 is a pick-up needle, 2 is a pick-up support structure, 3 is a detection section, and 4 is a housing.

The operation of the playback device configured as above will be described below. First, FIG. 2 shows the resonance characteristics of the resonance circuit of the detection section 3 including the reactance circuit formed between the pickup needle 1 and the video disk (not shown). In this Figure 2, the resonant frequency is set to ₀ . Due to a minute change in capacitance between the information signal on the video disk and the pickup needle 1, the resonance frequency ₀ changes minutely, and the signal is detected.

By the way, if the mounting positional relationship of the pick-up needle 1 and the detecting section 3 to the housing 4 is not constant (for example, the positions A and B in FIG. 1), the resonance characteristics will change, and at the same time, the resonance frequency ₀ will also change. Assuming that the resonant frequency at position A (detection unit 3 is indicated by the solid line in Figure 1) _{is 0a} , and the resonance frequency at position B (detection unit 3 is indicated by the dotted line in Figure 1) is _0b , then _0a and The level of the detection signal detected at the resonant frequency of _0b was different, and there was a problem that a good detection signal could not be obtained because the performance, such as the signal-to-noise ratio and frequency characteristics, were not constant. .

OBJECTS OF THE INVENTION It is an object of the present invention to provide a reproducing device in which the mounting positional relationship between the pick-up needle and the detection unit in the housing is always constant, eliminating variations in resonance characteristics and obtaining a good detection signal. There is a particular thing.

Structure of the Invention The playback device of the present invention includes a pick-up needle that extracts an information signal from a recording medium during relative scanning on the recording medium, a detection section that detects the information signal as a change in capacitance, and a pick-up needle that detects the information signal as a change in capacitance. and a housing for attaching the detection section and the pickup support structure, wherein a protrusion is provided integrally with the detection section, and the protrusion is brought into contact with the pick-up support structure. The sensor is configured to restrict the mounting position to the housing, thereby eliminating variations in the resonant frequency of the detection section and always obtaining a detection signal with good performance.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 shows the configuration of a playback device in an embodiment of the present invention. In FIG. 3, as in FIG. 1, 1 is a pick-up needle, 2 is a pick-up support structure, 3 is a detection section, and 4 is a housing.
Reference numeral 5 denotes a protrusion integrated into the detection section 3, which is a feature of this device.

The operation of the reproducing apparatus of this embodiment configured as described above will be explained below. First, the method of obtaining a detection signal is the same as in the conventional example. By the way, in this device, the pick-up needle 1 and the detection part 3 are integrated with the detection part 3 so that the mounting positional relationship between the detection part 3 and the detection part 3 is constant, and a protrusion part 5 is provided. Pick up support structure 2
Compared to the conventional example, a contact portion 6 is newly provided integrally. In this way, when the pick-up support structure 2 and the detection section 3 are attached to the housing 4, the protruding section 5 and the abutting section 6 are brought into contact with each other as shown in FIG. As described above, according to this embodiment, the resonant characteristic (resonant frequency) of the resonant circuit is always constant at ₀ because the mounting positional relationship between the pick-up needle 1 and the detection part 3 is always the same. has been realized. In the above embodiment, the abutting portion 6 is provided on the pickup support structure 2, but the length of the protruding portion 5 may be increased and the abutting portion 6 may not be formed.

Effects of the Invention As is clear from the above explanation, the present invention is configured so that the mounting positional relationship between the pick-up needle and the detection unit is uniform so that the resonance characteristics are always constant. A good signal with constant performance is obtained from the detected detection signal, and therefore, there is an excellent effect that the image reproduced from the video disc is always of good quality.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of a conventional capacitive reproducing device, FIG. 2 is a resonance characteristic diagram of a resonant circuit, and FIG. 3 is a configuration diagram of a capacitive reproducing device according to an embodiment of the present invention. be. DESCRIPTION OF SYMBOLS 1... Pick-up needle, 2... Pick-up support structure, 3... Detection section, 4... Housing, 5...
...protrusion.

Claims (1)

[Claims] 1. A pick-up needle for relative scanning on a recording medium, particularly for extracting an information signal from above the recording medium, and a detection section for detecting the information signal as a change in capacitance.
A pick-up support structure for holding the pick-up needle; a housing for attaching the detection section and the pick-up support structure; a protrusion is integrally provided on the detection section; A capacitance type regenerator configured to control the mounting position to the housing by making contact with the housing.