EP0218649A1

EP0218649A1 - An adaptator lens for a projection screen appliance such as a television set, a data display screen or the like

Info

Publication number: EP0218649A1
Application number: EP19860902334
Authority: EP
Inventors: Erwin Brandenstein
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-04-16
Filing date: 1986-04-16
Publication date: 1987-04-22
Also published as: WO1986006236A1; DE3513683A1

Abstract

Une lentille additionnelle pour un appareil à écran tel qu'un poste de télévision, un moniteur de visionnement de données ou similaire comprend une lentille ou une plaque de grossissement, une lentille en échelon de Fresnel par exemple. Afin d'améliorer la reconnaissance des caractères projetés sur l'écran et d'éviter que le spectateur ne soit ébloui ou soumis à des rayonnements, une plaque de filtrage (1) dont la construction fait l'objet des revendications dépendantes est placée devant la lentille de grossissement (7).An additional lens for a screen device such as a television set, data viewing monitor or the like includes a magnifying lens or plate, such as a Fresnel step lens. In order to improve the recognition of the characters projected on the screen and to prevent the spectator from being dazzled or subjected to radiation, a filtering plate (1) the construction of which is the subject of the dependent claims is placed in front of the magnification lens (7).

Description

Front optics for a display device, e.g. TV, display monitor or the like

The invention relates to a front lens system according to the preamble of claim 1.

10

Attachment devices for screen devices, television sets or the like are known, which are designed in the form of magnifying lenses, so-called Fresnel lenses, and are locked in front of the picture tube at a predetermined distance

15 can. Their task is to optically enlarge the picture shown on the picture tube or the like and to create a calm, largely flicker-free picture.

Especially in connection with screen devices, which also

If a keyboard is assigned, there is a need for attachment devices, since the screen and keyboard should be ergonomically arranged so that they can be overlooked at a glance. This in turn requires a certain minimum distance between the screen, which means that the characters are no longer perfectly legible for many viewers. Additional interference due to reflections can occur. In color data display devices, diffuse reflections of the incident light on the phosphor arranged behind the screen usually still occur.

~~ ® The safety regulations of the professional association from 01.01. 1985 require measures to reduce reflexes and meet the contrast values. The contrast, defined as the ratio between the luminance of the characters and the luminance of the background of the character, should be between 6: 1 and 10:10, the character

35 surface should not be less than 10 cd / m '^' . The person on the screen is additionally exposed to a high static charge, which varies between 10,000 and 30,000 volts depending on the type. In addition, exposure to radiation can also occur, especially UVA rays.

The present invention has for its object to improve an optical attachment of the type mentioned in the preamble of claim 1 in such a way that the legibility of the enlarged image and the correct attachment of the optical attachment and the maintenance thereof is improved, the reflections are reduced and part of the radiation occurring is shielded.

This object is achieved by the measures specified in the characterizing part of patent claim 1. Advantageous further developments and refinements of the invention result from the following patent claims.

With the present invention, an anti-reflective system is created by connecting a filter disc, preferably in a composite system with the magnifying lens, which ensures optimum readability of the images and characters shown and enlarged. It is particularly advantageous if the filter disk is designed as a disk assembly with, for example, two transparent disks which are tightly connected to one another and a filter film of a known type is arranged between the disks. Anti-reflective layers can be arranged on the outer sides and / or inner sides of the panes, preferably applied by vapor deposition. The anti-reflective layer preferably consists of a magnesium-titanium-silicon-m-fluoride. In the presence of curved screens or monitors, such as, for example, television sets, the magnifying lens or Fresnel lens must be adapted to the curvature of the picture tube with different focussing. It is important here that the disks or lenses of the composite system, including the monitor Darεllel, are arranged in relation to one another. A significant improvement in readability or recognizability The enlarged pictures or signs are obtained by the fact that the frame space between the filter disk and the magnifying lens is hermetically sealed from the outside and is preferably evacuated. In this way, optical errors, for example due to the penetration of dust particles or disruptive gases, can be avoided in the space mentioned.

Likewise for the benefit of legibility and ease of maintenance, the invention provides that the filter disk is preferably provided with an electrically conductive layer, which is connected to an earth loop to prevent electrostatic charges. A layer of indium tin oxide is preferably provided on the back of the glass.

To facilitate assembly and to prevent disturbing scattered light, it is further provided that the frame surrounding the optical elements has at the end of the device a collar which can be placed flush with the screen or monitor and adapted to it, such that the pane assembly is parallel to Screen or monitor. In this case, the assembly is made considerably easier and the flush fit of the optical attachment is improved in that the frame or envelope frame has a fastening device at the end on the device side. These are preferably clamping hooks which can be clamped to the monitor frame by means of screws which are accessible from the outside or which can be clamped in the gap between the screen and the frame.

Further advantageous details of the invention result from the exemplary embodiments shown in the drawing and described below. It shows

1 the composite or filter disc of the front lens as a detail,

2 shows the screen-side end of a television set in connection with an image-enlarging Fresnel lens,

3 shows the composite system with Fresnel lens and filter disk according to FIGS. 1 and 2,

4 shows the network system according to FIG. 3 in connection with a television set,

5 shows the front lens system surrounded by a hollow frame according to the preceding figures, placed on the screen of a television set in a perspective view with the area cut open,

6 is a sectional view of the connection point between the front lens and television set,

Fig. 7 is a sectional view of the front of the television set and the associated optics.

The filter disc 1 shown in side view in FIG. 1 consists of two transparent panes, for example glass panes 2 and 3, and a filter foil 4 arranged between them, which is intended to keep disturbing or harmful radiation away from the viewer's eye. The aforementioned ^TeiJ: _ 2, 3 and 4 are fixedly connected to each other and constitute a composite disk 2 shows the curved screen 5 of the display tube 6 in turn provides a television set not shown in side view darge.. At a predetermined distance in front of the screen 5, for example at a distance of 6 to 7 cm, a magnifying lens in the form of a Fresnel lens 7 is connected upstream of the screen 5. This Fresnel lens 7 is planar with different focusing angles.

8AD ORIGINAL tion adapted to the curvature of the picture tube. On the surface of the Fresnel lens 7 facing the screen 5, the grooves 8 formed by the division into individual ring lenses or prisms are located in accordance with the adjusted focusing.

FIG. 3 shows a sectional view of a composite system consisting of Fresnel lens 7, composite filter disc 1 and a frame 9 comprising the two aforementioned optical element. The tubular frame 9, for example, has annular grooves 10 and 11 arranged at a distance from one another in the inner wall surface 2, wherein in the annular groove 10 is the composite filter disc 1 and the Fresnel lens 7 is inserted tightly into the annular groove 11. The seal between the optical elements and the frame 9 in such a way that the frame space 12 between the optical elements 1 and 7 is hermetically sealed from the outside and is preferably evacuated. In Figure 3 sin ;! above ^'and below the optical axis Mittel¬ planar or two different Ausführungsfor¬ men shown of the aforementioned optical elements. In the upper half, the composite filter disk * 1 has an anti-reflective layer 13 on the outside of the observer, for example in the form of a vapor-deposited layer of metal oxide or the like, while the grooves 8 of the Fresnel lens 7 are arranged towards the inner frame space 12, the outside of the device the Fresnel lens 7, however, is completely flat. In the exemplary embodiment in the lower half according to FIG. 3, both sides or surfaces of the composite filter disc 1 are provided with the anti-reflective layer or vapor deposition 13. Here are the grooves 8 on the device side: towards the outside of the Fresnel lens 7, the inside of which is completely p ¹ Ή. As the figure shows, Fresnel lens 7 and _. Filter disc 1 arranged exactly parallel to one another and thus held in the frame 9. Frame 9 and optical elements 1 and 7 together represent a composite system 14.

FIG. 4 shows the aforementioned composite system 14 in an arrangement in front of the picture tube 6 of a television set 15.

BAD ORIGINAL On the outer side surface of the filter disk 1 there is a transparent, electrically conductive, for example vapor-deposited coating 16, which can be identical to the anti-reflective coating 13 according to FIG. 3. An electrical grounding loop 17 is connected to this coating 16, which in turn is connected to the ground connection 18 of the television set 15. In this way, an electrostatic charging of the front optics is avoided. The figure shows that the composite system 14 is arranged exactly parallel to the screen level or that the optical axes are aligned with one another.

In the exemplary embodiment according to FIGS. 5 and 6, the composite system 14 is firmly inserted into a dimensionally stable envelope frame 19, for example made of plastic material. This envelope frame 19 is designed in the form of a cobus and is open on both sides. It has a collar 20 which projects beyond the Fresnel lens 7 at a predetermined distance of, for example, 6 to 7 cm and which at its free end is adapted to the rectangular shape of the screen 5 or the frame 21 on the device side, which limits the viewing area of the screen 5 is. From this free end, the envelope frame 19 widens like a funnel to the composite system 14. At the end remote from the device, the enveloping frame 19 has a diaphragm part 22 which at least projects upward above the filter disk 1. Of course, there is also the possibility of using the enveloping frame 19 itself as a composite frame for Fresnel lens 7 and filter disk 1, as shown in FIG. 5 FIG. 7 the composite system 14 together with the composite frame 9 inserted, for example glued, into the casing frame 19 '. FIG. 7 also shows the cross-sectional profile of the enveloping frame and the flush support of the collar 20 on the screen 5 of the television set 15. Clamping hooks 23 are used for the releasable fastening of the enveloping frame 19 or 19 'to the television 15, each paired on both sides the envelope frame corners are arranged. As particularly shown in FIG. 6, each clamping hook 23 has a bent hook Leg 24 and a support leg 25 and a threaded bore between the legs. In a slot-like opening

26 is inserted into the collar 20 of the casing frame 19, a screw 27 which is screwed to the threaded bore of the clamping hook 23. After placing the Hüllrahmeπs 19 on the screen 5, each clamping hook 23 is moved in the slot-like ^" opening 26 so that the hook leg 24 protrudes into the gap between the screen and frame 21. By tightening the screw

27, the clamping hooks 23 are clamped in this gap 28, so that the front lens system is now firmly connected to the television set 15. When screwing tight, the support leg 25 serves as a clamping abutment.

Of course, there is also the possibility to arrange a Velcro between screen 5 or frame 21 and envelope 19.

Claims

1. Optical attachment for a display device, e.g. TV set, data display monitor or the like with a magnifying lens or disc. e.g. Fresnel lens, characterized in that a filter disc (1) is connected upstream of the magnifying lens (7).

2. Front lens system according to claim 1, characterized in that the filter disc (1) is designed as a disc assembly with at least two tightly connected transparent discs (2, 3). i

3. optical attachment according to claim 2, characterized in that a ^' filter film (4) is arranged between the discs (2, 3).

4. attachment optics according to one of the preceding claims, characterized in that the pane assembly (1) is designed as an anti-reflective disc, preferably 'on the outer surfaces with an anti-reflective layer (13) e.g. is provided by vapor deposition.

5. optical attachment according to claim _. 4, characterized in that a magnesium-titanium-silicon-fluoride layer is applied as the anti-reflective layer.

6. optical attachment according to claim 5, characterized in that a layer of indium tin oxide is attached to the back.

7. header ik according to any one of the preceding claims, characterized in that the filter disc (1) with an electrically conductive layer (16) is preferably Be¬ coating, the verbun¬ to prevent electrostatic charges with a ground loop (17) is.

8. attachment optics according to claim 7, characterized in that the electrically conductive layer (16) to the ground connection (18) of the downstream device (15) is bar.

9. attachment optics according to one of the preceding claims, characterized in that the filter disc (1) forms a composite system (14) together with the magnifying lens (7) parallel to the filter disc.

10. Optical attachment according to 'Claim 9, characterized in that the composite system (14, 14) a frame (9, 19) e.g. the filter disc (1) and the magnifying lens (7) encompassing time. in tube form.

11. Optical attachment according to claim 10, characterized in that the frame space (12) between the filter disc (1) and the magnifying lens (7) is hermetically sealed to the outside and is preferably evacuated.

12. Optical attachment according to one of the preceding claims, characterized in that the frame (19, 19 ') at the end of the device has a collar (20) which can be placed flush on the screen (5) or monitor and adapted to it, in such a way that the Disc connection is parallel to the screen or monitor.

13. Front lens system according to claim 12, characterized in that the frame (19, 19 ') designed as a tube extends from the collar (20) to the magnifying lens (7) in a funnel-like manner.

14. Optical attachment according to claim 13, characterized in that the frame (19, 19 ') at the end remote from the device has an at least partially protruding diaphragm part (22) over the filter slide (1).

15 attachment optics according to one of the preceding claims, characterized in that the composite system (14) of filter slide (1) and magnifying lens (7) in a composite frame (9) is attached, which in turn in an outer, on the screen (5) or The monitor can be attached to the cover frame (19, 19 ').

16 .. front lens for a display device, e.g. TV, data display monitor, or the like, in particular according to one of the preceding claims, characterized gekenn¬ characterized in that its envelope frame (19, 19 ') has at the end of the device a fastening device with which the front lens can be attached flush to the screen (5).

17. Auxiliary optics according to Arsoruch 16, characterized in that in the corner areas oπ, preferably on both sides of the envelope frame corners, clamping hooks (23) are arranged, which can be clamped with the device (2) comprising the screen (5), preferably in the gap (28) can be clamped between the screen and the frame.