KR850003349Y1 - Apparatus for writing and reading information on a rotary information disc with the aid of readation beam - Google Patents

Abstract

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Description

Apparatus for recording and reproducing information on a rotating information disc as a radiation beam

1 is a perspective view of a video disc player with the cover open.

2 is a perspective view of a mounting unit incorporated into the video disk plug of FIG.

3 is a cross-sectional view of the device of FIG. 2 taken along line III-III.

4 is a perspective view of a modified video disc player.

5 is a perspective view of a mounting unit modified for the video disc player of FIG.

6 is a perspective view of a video camera having an information disc on which video information is recorded.

The rod design relates to a device for recording and / or reproducing information as a radiation beam on an information surface of an information disk rotating about an axis of rotation, said device being radiated to form a radiation point in a main frame, an object frame, a focal plane. An objective lens having a lens system having one or more lenses and a free end directed towards the information disc, and a parallel guiding device for guiding the movement of the objective lens along the optical axis to focus the beam; It is provided.

Such a device is known from US Pat. No. 3,977,684. In a device known in the patent, namely a video disc player, the main frame has a cabinet with radial grooves in which the objective lens can be moved by a movable object lens frame.

Since dust enters the inside of the device through the open groove in the cabinet of the video disc, and the user can contact the driving part of the device through the open groove, the groove in the known video disc moves together with the objective lens frame. It is sealed by. The closure device may for example consist of a strip which moves together with the objective lens and is guided over the roller. It is also desirable that the objective lens itself is protected from dust, individual damage and contact. This is because the objective lens is an expensive and relatively weak component and at the same time there should be no contaminants on the lens surface facing the information disc. Therefore, it is good to clean the lens surface regularly, which means that the objective lens is subjected to mechanical load.

It is an object of the present invention to provide a device of the type mentioned in the foreword in which the objective lens is well protected. The device is connected to the main frame so as to extend transverse to the optical axis at a position between the lens system and the rotating information disk, so that a radiation beam permeable shield for shielding the objective lens from dust, contaminants and mechanical damage is provided for free termination of the movable objective lens. It is arranged parallel to a fixed plane in the vicinity and is characterized in that the lens system is modified for the optical properties of the shield.

The present invention effectively shields the movable objective lens. However, there is a need for maintaining a sufficient working distance between the objective lens and the rotating information disc. It is possible to develop an objective for an optical video disc player with an operating distance of about 4 mm, and also a larger working distance. Obviously, the surface of the shield facing the information disc must also be kept clean. Therefore, regular contact with the surface of the shield is inevitable. However, when contacting the device, the objective lens or the objective frame is not subjected to any load. Note that this view discloses the type of parallel plane optical element inserted between the objective lens and the rotating information disc in the device of the type mentioned in the foreword in US Pat. No. 1,855,426.

The presence of an optical element in the device determines whether or not the information track on the information disc is reproduced. Since the parallel plane optical element can move without being fixedly mounted on the main frame of the device, it is not composed of a shielding device that can protect the objective lens against contaminants, dust, and mechanical damage.

One embodiment of the present invention is characterized in that the shielding device includes a parallel plane shielding plate having a thickness of 0.5 mm or less. If the parallel plane shield has a thickness of about one tenth of a millimeter, the lens system needs only minimal calibration. In a video disc player, if the light beam emitted by the lens system has a diameter of 10 mm or less, the shield plate will have a width of 8 mm. For this small width of the shield, a few tenths of millimeters of thickness will not necessarily result in poor fragility of the shield.

According to another embodiment of the present invention, as the objective lens frame moves with respect to the main frame, the peripheral position of the first maximal position and the information disc in which the objective lens is closer than the second maximal position with respect to the passage of the main frame, that is, the rotation axis of the information disc It is to use a device of the type mentioned in the foreword that travels between the second maximal position closer to the first maximal position. As already stated, such a device is known from US Pat. No. 3,977,684.

This embodiment has the property that the shield extends over the passage length between at least a first maximal position and a second maximal position. When this embodiment is used, the shield also has a dual function, since the shield has the same function as the closure device with respect to the grooves formed in the cabinet of the device. In addition, an additional advantage of this application is that a more interesting form is obtained. The user of the video disc player to which the present embodiment is applied will never see the driving portion of the objective lens system in the apparatus. Only the drive side of the tentable to support the video disc will protrude from the deck.

Note that another embodiment of the present invention in which the shield plate is molded into a polyamide thin plate so that the parallel plane shield plate in the apparatus according to the embodiment of the present invention already mentioned has the maximum mechanical strength. Many suitable optical properties are a matter of concern, and polyamide thin plates have inadequate properties in which double refraction occurs due to internal stresses induced in the material by mechanical actuation. However, in the case of molded polyamide sheets, this disadvantage is reduced and can be practically eliminated.

Another embodiment is characterized in that the objective lens is arranged in a suture enclosing the objective lens so that dust does not actually enter and the shielding device forms part of the suture. This embodiment has important additional advantages. The movement of objective lenses in optical video disc players has been known to be the main cause of the simulated sound of video discs. Due to the irregularity of the position of the video disc information surface, refocusing movement on the objective lens is inevitable while the disc is rotating.

This refocusing movement is automatically controlled by the electrical hold control element provided for this purpose. Since the video disk rotates at a speed of 25 to 30 revolutions per second based on frequency, the movement of the objective lens has a fundamental frequency of 50 Hz or 60 Hz, respectively. There are also several harmonics at frequencies up to several KHz. The human ear is very sensitive to air vibrations within this frequency range. Therefore, it is very important to place the objective lens in the suture as much as possible to suppress the noise as much as possible.

If a device is constructed according to the already mentioned embodiment in which the objective lens can move between the first and second maximal positions, ie from the center of the information disc toward the periphery, between the shield and the slightly struck information disc edge. There is an improved embodiment of the present invention that is important for preventing undesirable contact. This embodiment has the characteristic that at least one stationary roller is arranged on the main frame near the second maximal position of the objective lens for rolling contact with the edge of the information disc. In the case of an information disc that is slightly struck, the stop roller contacts only the peripheral portion of the information disc when the operating speed of the disc is accelerated. The centrifugal force exerted on the information disc by the fast rotation straightens the disc in a plane perpendicular to the axis of rotation. A shielding device is connected to the main frame near the first maximal position of the objective lens frame so that the shielding device can be pivoted about the pivot side perpendicular to the rotation axis of the information disk, and the objective device and the shielding device cooperate with each other. And another embodiment of the present invention, wherein the shield is retracted from the inclined position to the horizontal position and vice versa when the objective lens frame is moved from the first maximal position to the second maximal position. have.

The present invention will be described in detail with reference to the drawings with respect to several embodiments.

The video disc player of FIG. 1 has a main frame, which has a cabinet 1 having a plurality of control elements 2 on its front side for controlling various functions. At the center of the cabinet is a concave surface 3 which can be covered by the hinge cover 4. The drive shaft 6 extends through the actual planar deck 5 in the concave surface 3. The shaft is provided with a concentrating member 7 for the video disc 21 and the turntable 8. The cover has a disc loader 9 which is movable to the opposite position of the concentrator, which magnetically cooperates with the concentrator in order to secure the video disc to the support table. In the cabinet 1, a mounting unit 10 (see also FIG. 2) belonging to the main frame is mounted, and the unit is provided with a subframe 11. The subframe has a profiled injection molding in which the lid 4 is hinged. In addition, the subframe houses all the optical and mechanical elements necessary to operate a video disc player, such as a drive shaft 60 with a concentrating member 7, a support table 8 and a drive motor (not shown) for the drive shaft. The subframe also has a movable objective lens frame 16 through which the laser 12, a plurality of optical elements 13, 14, 15 and the objective lens 17 are guided to move within the frame. See US Pat. No. 4,021,101 for further information regarding the construction of the objective lens frame and its cooperation with the objective lens. In the objective lens 17, a lens system having an optical axis 18 is arranged, and can move up and down along the optical axis. In order to guide the objective lens along the optical axis 18, a bearing bush 19 is firmly connected to the objective lens frame 16.

Near the free end 20 of the objective lens 17, a radiation beam permeable shield 22 for shielding the objective lens 17 from dust, dirt and mechanical damage is provided with a lens system of the objective lens 17 and a rotating video disk ( At positions between the installation sites of 21), the optical axis 18 is arranged parallel to the fixed plane connected to the main frame so as to extend laterally.

The objective lens frame 16 can be moved along the linear guide on the subframe 11 by a drive motor (not shown).

As shown in FIG. 3, the linear guide has a flat guide passage 24 through which the rod 23 and the roller 25 move. See also FIG. 5 showing a modified embodiment of the present invention where the subframe and the object lens frame are identical except for some details.

The laser 12 makes light beams, which enter the objective lens 17 through the optical elements 13, 14 and 15, among others. By the reflection of the beam focused on the information surface of the video disc 21, the light beam is returned back to the inside of the video disc player via the objective lens 17 and the optical elements 15, 14 again. Video signals and audio signals are not related to the present invention, such as signals necessary for automatic control of the movement of the objective lens frame 16 and the objective lens 17 and signals required for any other moving element in the common path of the video disc player. It is obtained by converting light beam modulation to electrical modulation with the aid of.

The shield 22 has a parallel flat shielding plate having a thickness of 0.5 mm or less. The objective lens frame 16 can move to the main frame. The objective lens 17 associated with the main frame and also the subframe 11 is a straight path between the first maximal position near the rotation axis 26 of the video disk 21 and the second maximal position near the circumference of the video disk. To track. The shield 22 extends over the entire length of the passageway between the first and second maximal positions. The shielding plate may for example be a template polyamide thin plate.

As shown in FIG. 2 and FIG. 3, the objective lens 17 is surrounded by the enclosure 27 so as to prevent dust from actually entering therein, and the shielding device 22 is a part of the enclosure. Form. The shielding plate may be connected to the base of the suture, for example by glue, clasp or R, F welding. The subframe 11 is designed such that the portion covered by the suture 27 is also closed at the bottom. As a result, the objective lens 17 is accommodated in the completely sealed space, thereby being well shielded from dust or mechanical damage. The suture contains not only the objective lens but also the optical element in the optical path. The laser 12 is provided outside the enclosure 27.

Another important advantage of this embodiment of the present invention is to attenuate the annoying noise caused by the refocusing movement of the objective lens 17 in an effective manner.

When the video disc player is operating, it is inclined near the second maximal position of the objective lens 17 so that no contact occurs between the enclosure 27 having the shield 22 and the edge of the slightly inclined video disc. Two stop rollers 28 are placed on the main frame in contact with the edges of the video disc.

4 and 5 relate to the same video disc player as the apparatus of FIGS. 1 to 3 except for the apparatus for shielding the objective lens. The same elements as those shown in FIGS. 100 is designated as the reference number larger than the element in FIG. The shield consists of a shield plate 140 made of a suitable radiation beam transmissive plastic.

The shield plate forms part of the deck 105 which constitutes the bottom of the concave portion 105 in the cabinet of the main frame 101. In this embodiment the movable objective lens 117 extends the shielding plate over the entire length of the path associated with the subframe 111. Subframes belonging to the main frame near the first maximal position of the objective lens system 116 installed near the drive shaft 106 so that the shield plate 140 does not come into contact with the edge of the slightly displaced video disc when the video disc player is operated. Connect the shield plate to the 111). According to this result, the shield plate rotates about the pivot shaft 141 perpendicular to the rotation axis 126 of the video disk between the inclined position and the horizontal position shown in FIGS. 4 and 5. When the objective lens is in the second maximal position near the video disk edge, it reaches a horizontal position. The device for pivotally connecting the shield plate 140 to the subframe 111 may be two pivot pins 142 placed one on each side of the shield plate.

The distillation lens frame 116 and the shielding plate 140 are provided with a cooperating fever device. The device consists of a ridge 143 on the bottom surface of the shield plate 140 and the objective lens frame. As shown in FIGS. 4 and 5, when the objective lens frame is moved from the first maximal position to the second maximal position, the shielding plate 140 is secured by cooperating with the bottom of the shielding plate 140 and the ridge 143. It is pivoted from the photographic position to the horizontal position. When the objective lens frame is returned, the shield plate is pivoted back from the horizontal position to the inclined position. The shielding plate may be pivoted back to the inclined position due to its weight, but may be propelled in the direction of the inclined position by the elastic device.

6 shows an electronic camera applied to recording video information on the rotating information disk 150. As shown in FIG. The camera includes a main frame 151 on which a pivot cover 152, an objective lens 153, a viewfinder 154, a handle 155, and controllers 156 and 157 are disposed. The information disc 150 may be close to the tentable 158 in which the concentrating element 159 is installed, and the information disc is fitted into the element by its intermediate hole 160. The lid 152 is provided with a disc loader, not shown, for loading the information disc on the tentable 158. The main frame 151 has a substantially flat frame plate 161 extending across the axis of rotation 162 of the information disc. Part or all of the frame plate transmits a radiation beam, and constitutes a shielding plate for shielding an objective lens that can move within the housing 151 of the camera. Video information can be recorded on the information disc through the objective lens as a radiation ratio. The information disc may belong to the format described, for example, in US Pat. No. 4,074,282 (see here).

Claims (1)

While moving with respect to the main frame 1, the objective frame 16, and the objective lens frame, the radiation beam is focused through a transparent layer to form a radiation point on a focal plane coinciding with the information surface, and several lenses and optical axes An objective lens 17 having a lens system having a free end 20 in a direction toward the information disc, and a parallel guide device 19 for guiding the movement of the objective lens along the optical axis. A device for recording and / or reproducing information through a transparent layer by having a radiation ratio on a reflective information surface of a rotating information disk, wherein the free end 20 of the movable objective lens 17 is free from dust, dirt and mechanical damage. A radiation beam transmissive shield 22 for shielding the objective lens traverses the optical axis 18 at a position between the lens system and the installation location of the rotating information disk 21. Device characterized in that disposed in parallel to the connected to the main frame 1 to extend in a fixed plane.