Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
1998-03-25
2001-01-16
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C250S216000
Reexamination Certificate
active
06175106
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an optical arrangement comprising a plurality of light transmitting transmitter elements and/or receiver elements formed for the reception of light, a plurality of diffractive/refractive optical elements and a transparent front cover, in particular a front plate. Furthermore, the invention is directed to a light grid having at least one optical arrangement with transmitter elements and also at least one optical arrangement with receiver elements of this kind, and also to a method of manufacturing the individual elements of corresponding optical arrangements.
DESCRIPTION OF THE PRIOR ART
Optical arrangements of this kind, i.e. transmitter and receiver apparatus, and also light grids formed from them are, for example, used with automatically closing doors, such as lift doors. In earlier times, only one respective transmitter and receiver element was provided at the sides of the door opening. Nowadays, a plurality of transmitter and receiver elements are increasingly arranged at the door opening and are distributed over the height of the door opening for safety reasons. The aim is to achieve a situation in which both narrow articles, which enter into the detection zone disposed within the door frame, such as for example sticks, fingers or dogleads, and also articles which enter the doorway over the whole region of the height of the door, can be reliably recognised.
In order to be able to produce a light grid which is ideally matched to the height of a particular door or doorway it is necessary, having regard to the large number of different heights of the different doors, to keep a large number of different pieces of optical transmitter and receiver apparatus in store, or these apparatuses must be individually manufactured for each door. This leads, on the one hand, to high storage costs and, on the other hand, to high production costs, because the production of light grids having a plurality of different heights reduces the numbers manufactured for each particular height, and thus practically equates to individual manufacture.
OBJECT OF THE INVENTION
The present invention is based on the object of designing a light grid of the initially named kind, and also the optical transmitter and receiver apparatuses required for the light grid, so that a very simple and cost-favourable manufacture of these components is possible and, at the same time, so that the light grids which are produced can be variably used for almost any desired height of a monitored zone. Furthermore, a method should be set forth for the simple and cost-favourable manufacture of the individual elements required for a light grid formed in accordance with the invention.
The object of the invention relating to the apparatus is satisfied in that the diffractive/refractive optical elements are arranged on a uniform carrier element formed in one piece; in that the carrier element is formed by the front cover and the diffractive/refractive optical elements are directly formed in the front cover, and are in particular pressed into the latter, or moulded into the latter, and in that the transmitter and receiver elements are arranged on a uniform circuit board formed in one piece.
A light grid designed in accordance with the invention comprises at least one of these optical transmitter and receiver apparatuses.
The part of the object relating to the method is solved by the features of claims
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BRIEF DESCRIPTION OF THE INVENTION
Thus, in accordance with the invention, the important components of the optical light grid, namely the diffractive/refractive optical elements, and also the circuit board(s) which carry(carries) the transmitter and/or receiver elements are formed in the ideal length required from elements manufactured as “goods by the metre” by simple measurement and cutting. With this arrangement, a further reduction of the number of elements that are required, and thus a further cost reduction, is achieved by the formation of the diffractive/refractive optical elements directly in the front cover. In addition, a situation is made possible in this way in which the diffractive/refractive optical elements which originally represented separate individual parts can be prepared as “goods by the metre”.
A further advantage of combining the front cover and the diffractive/refractive optical elements into a uniform component lies in the fact that a separate lens manufacture can be omitted and the optical elements can, for example, be formed by pressing the non-treated transparent front cover in a continuous process and can thus be manufactured economically with constant quality in an “endless process”.
In practise the circuit board can also be automatically equipped with the electronic components in a continuous process, whereby the quality of the automatic mounting of these components can be increased. In addition, no connections are necessary between individual circuit boards, for example via plug connections or soldered connections, whereby the problems which are often associated with this problem are likewise avoided.
The testing of the so equipped circuit boards can also be carried out directly after the mounting of the components in the same method step, whereby the costs can be further reduced and the quality can simultaneously by increased. The cutting off of the individual element sections can take place by cutting, by fracture, by sawing or the like, depending on the materials used.
In accordance with an advantageous embodiment of the invention a plurality of diaphragm apertures is provided between the circuit board carrying the transmitter and/or the receiver elements and the front plate forming the diffractive/refractive optical elements, with the diaphragm apertures being formed in a uniform diaphragm plate, preferably in one piece. This diaphragm plate can be manufactured in accordance with the manufacture of the circuit board or of the front cover in an endless method, so that when manufacturing a light grid of the desired length, it is only necessary to cut off a corresponding section of the prepared diaphragm plate material. Through the diaphragm plate the scattering between adjacent transmitting and/or receiving elements is reduced, whereby the response accuracy of the light grid is enhanced.
The centre-to-centre spacings of two adjacent diffractive/refractive optical elements, of two adjacent transmitter elements, of two adjacent receiver elements and optionally of two adjacent diaphragm apertures are of substantially the same size. Through this arrangement, and also through the one-piece design of the front cover, and also of the circuit board and of the diaphragm plate, it is ensured, through simple adjustment of the front cover carrying the diffractive/refractive optical elements with respect to the respective circuit board, and optionally with respect to the diaphragm plate, that all transmitter and receiver elements are aligned in a single process with all the diffractive/refractive optical elements and also optionally with all the diaphragm apertures. An adjustment of the position of individual elements is thus not required.
The sizes of the diaphragm apertures are advantageously variably adjustable, whereby a stepless adaptability to different customer wishes can be achieved.
In accordance with a further advantageous embodiment of the invention, the circuit board and/or the front cover and/or the diaphragm plate are flexible, and are in particular each formed as a flexible foil. In this manner, the light grid can be tailored very individually to have any desired shape, so that it can, for example, be adapted to extend along a predetermined curvature. Furthermore, the manufacture of flexible front covers with integrated diffractive/refractive optical elements and the manufacture of flexible circuit boards or diaphragm plates can be produced in a “reelto-reel” process. In this way, the premanufactured base materials are unwound, are passed to respective devices suitable for the pressing in of the diffractive/refractive elements, for the mou
Buitkamp Hermann
Hippenmeyer Heinrich
Le Que T.
Sick AG
Townsend and Townsend / and Crew LLP
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