ELECTRONIC DEVICE

Abstract: The invention relates to a device for reading information stored on an information plate (2) and/or writing information on an information plate (2). The invention is characterized in that the device comprises at least one position switch (1) for recognizing the position of the information plate (2), in that the position switch (1) comprises at least two detection elements for scanning two mutually distanced reference points, and in that said reference points are arranged on the circumference of a circle whose center corresponds to the center of the information plate (2) in a reference position.

Description: Electronic device. The invention relates to a device for reading information stored on an information plate and/or for writing information on an information plate. Such a device is known, for example, from the publication EP 0892403. The term information plate here is understood to mean a disc-shaped data carrier, in particular a CD, CD-ROM, and DND. In the known device, a mechanical stop is provided against which the information plate is abutted during the loading process for the purpose of positioning the information plate above the turntable of a playback unit. It is an object of the invention to provide a device of the kind mentioned in the opening paragraph which renders possible an accurate positioning of an information plate on the turntable of a playback unit. According to the invention, this object is achieved in that the device comprises at least one position switch for recognizing the position of the information plate, in that the position switch comprises at least two detection elements for scanning two mutually distanced reference points, and in that said reference points are arranged on the circumference of a circle whose center corresponds to the center of the information plate in a reference position. It is possible with such a position sensor to detect the position of the information plate exactly in two dimensions and to position the information plate exactly in a desired location in two dimensions. In particular, the position sensor is suitable for an exact positioning of the information plate above the turntable of a playback unit. The reference position in this case is the center of the turntable. The advantageous embodiment of the invention as defined in claim 2 is particularly inexpensive and simple to realize. The optical solution as defined in claim 3 can be integrated into compact devices in a particularly space-saving manner. The optical contact pairs each form a photoelectric barrier. The photoelectric barrier is interrupted the moment the plate edge of the information plate reaches the relevant reference point. The advantageous embodiment of the invention as defined in claim 4 has the advantage that the positions of the two reference rims with respect to one another can be manufactured with very narrow tolerance in stamping technology. The advantage of this construction is that the switching point can be maintained very accurately without adjustment. The embodiment of the invention as defined in claim 5 has the advantage that the contacts still move relative to one another after closing. This achieves a self-cleaning effect of the contacts. At the same time, the reference rims for the edge of the information plate must be kept fixedly positioned with respect to the center of the turntable. To achieve this, the reference rims are rigidly fastened in the housing of the switch, whereas the contacts are fastened to resilient spring arms. The embodiment of the invention as defined in claim 6 has the advantage that the connection of the two contacts inside the switch reduces the expenditure for contacting by means of cables or foils. It is advantageous for reasons of space in devices as defined in claim 7, which comprise a stacking function in addition to the playback function (changer devices), when the transport of the information plates to the turntable can take place in two loading directions. A first loading direction is, for example, the transport of the information plate from an ejection position outside the device onto the turntable, while a second loading direction is, for example, the transport of the information plate from the stacking unit to above the turntable. The exact position of the information plate above the turntable can be detected two-dimensionally by means of the position sensor according to the invention so as to lay the information plate on the turntable subsequently such that the centering pin of the turntable enters the central hole of the information plate. A diagrammatically depicted embodiment of the invention will now be explained in more detail below with reference to the drawings of Figs. 1 to 3, in which: Fig. 1 is a plan view of a position switch for the two-dimensional detection of the position of an information plate, Fig. 2 shows a component of the position switch in perspective view, and Fig. 3 is an enlarged view of the contacting region of the component of Fig. 2. Fig. 1 shows a position switch 1 which is provided for the exact positioning of an information plate 2 on a turntable 8 of a device for reading information stored on the information plate and/or writing information on the information plate 2. The position switch 1 comprises as its detection elements a first pair of contacts with contacts 4a/5a and a second pair of contacts with contacts 4b/5b. The contacts 4a/5a and 4b/5b are provided on respective spring arms 5d, 5g. The position switch 1 has reference rims 3a and 3b for the edge of the information plate 2 and reference rims 5c and 5f for the contacts 4a and 5a. The spring arms 5d in their non-operational position bear with force on the reference rims 5c and 5f. Operational elements 6a, 6b are present at the spring arms 5g, providing a larger effective surface area for the plate edge of the information plate 2. In Fig. 1, the information plate 2 rolls with its outer edge along the reference rim 3a, thus exactly closing the pair of contacts 4a/5a. The correct position above the turntable 8 is reached when also the second pair of contacts 4b/5b is closed. This happens when the information plate 2 is moved further in the direction of arrow A. The switching points of the contact pairs 4a/5a and 4b/5b are situated such that both switches are operated when the information plate 2 has occupied the correct position above the centering pin 8a of the turntable 8 with its centering hole 2a. The situation is to be viewed as in a mirror with axis S for the transport of the information plate in the reverse direction. The information plate 2 can thus be exactly positioned two-dimensionally above the turntable 8 by means of the positioning switch 1. Fig. 2 shows the component of the position switch 1 which carries the contacts 4a and 5a in perspective view. The contact 5a is positioned as close as possible to the reference rim 5c so as to keep the influence of the bending of the spring arm 5d small. The reference rim 3a for the information plate 2 lies on the same component as the reference rim 5c, so that the positions of the two reference rims with respect to one another can be manufactured with very narrow tolerance in stamping technology. The same holds for the reference rims 3b and 5f. The advantage of this construction is that the switching point can be maintained very accurately without adjustment. When the switch is operated, the contacts 4a and 4b first abut against the contacts 5a and 5b, respectively, which are supported with force against the reference rims 5c and 5f, whereby the switching point is defined. To achieve a self- cleaning effect of the contacts, it is necessary for the contacts still to move relative to one another after closing. On the other hand, the reference rims 3a and 3b must be kept fixedly positioned with respect to the center of the turntable 8. To comply with both requirements, the component shown in Fig. 2, which comprises the contacts 5a and 5b, the reference rims 5c and 5f, and the reference rims 3a 3b, is constructed such that the reference rims 5c/5f, 3a/3b are rigidly fastened in the housing of the switch, whereas the spring arms 5d are constructed as additional resilient components. Fig. 2 furthermore shows a connection 5e which renders possible the electrical contacting for the two contacts 5a and 5b. The connection of the two contacts 5a and 5b inside the switch reduces the expenditure necessary for contacting by means of cables or foils. Fig. 3 shows a detail of the contacting region with the reference rims. The spring arm 5d is slightly lifted off the reference rim 5c here. This is achieved in that the contact 4a not shown in Fig. 3 presses against the contact 5a and thus acts on the spring arm 5d.

Claims: CLAIMS: 1. A device for reading information stored on an information plate (2) and/or for writing information on an information plate (2), characterized in that the device comprises at least one position switch (1) for recognizing the position of the information plate (2), in that the position switch (1) comprises at least two detection elements for scanning two mutually distanced reference points, and in that said reference points are arranged on the circumference of a circle whose center corresponds to the center of the information plate (2) in a reference position. 2. A device as claimed in claim 1, characterized in that the position switch (1) comprises as its detection elements at least two pairs of electrical contacts (4a/5a, 4b/5b) with actuator elements (6a, 6b) which are designed for scanning the plate edge of the information plate (2), while the switching points of said pairs of contacts (4a/5a, 4b/5b) correspond to said reference points. 3. A device as claimed in claim 1, characterized in that the position switch (1) comprises as its detection elements at least two pairs of optical contacts (4a/5a, 4b/5b) which are designed for scanning the plate edge of the information plate (2), while the switching points of said pairs of contacts (4a/5a, 4b/5b) correspond to said reference points. 4. A device as claimed in claim 2, characterized in that the position switch (1) comprises at least two reference rims (3a, 3b) for the edge of the information plate (2) and at least two reference rims (5c, 5f) for at least one contact of each of the two pairs of contacts (4a/5a, 4b/5b), and in that the relevant reference rims (3a, 3b) for the edge of the information plate (2) and the reference rims (5c, 5f) for the contacts of the pairs of contacts (4a/5a, 4b/5b) are arranged on one integral component of the position switch (1). 5. A device as claimed in claim 4, characterized in that the two contacts of each pair of contacts (4a/5a, 4b/5b) are provided on spring arms (5d, 5g). 6. A device as claimed in claim 2, characterized in that one contact of each pair of contacts (4a/5a) is connected to a respective contact of the other pair of contacts (4b/5b) with electrical conduction. 7. A device as claimed in claim 1, characterized in that the device is constructed as a changer device and comprises a stacking unit for the storage of at least two information plates (2).

Inventors: KUNZE NORBERT, MUELLER STEFAN, RUMPF HORST, KUNZE, NORBERT, MUELLER, STEFAN, RUMPF, HORST
Applicants: KONINKL PHILIPS ELECTRONICS NV, KUNZE NORBERT, MUELLER STEFAN, PHILIPS CORP INTELLECTUAL PTY, RUMPF HORST, KONINKLIJKE PHILIPS ELECTRONICS N.V., KUNZE, NORBERT, MUELLER, STEFAN, PHILIPS CORPORATE INTELLECTUAL PROPERTY GMBH, RUMPF, HORST
Application year: 2000
Main classification: G11B19
IPC codes: G11B17, G11B19