JP2010057180A - Detector of broken screen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and a method for easily detecting a broken screen or a damaged screen. <P>SOLUTION: The system for detecting screen damage for a laser PTV (Projection Television) includes: conductive traces arranged on a surface of the display screen of the PTV; and a damage detecting circuit which is connected with the conductive traces and is configured so that it detects discontinuity in the conductive traces due to the screen damage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  Embodiments described herein relate generally to televisions, and more particularly to laser source-based televisions, and more particularly to systems and methods that facilitate detection of broken or damaged screens. About.

(Background information)
In laser projection television (PTV), a laser light source is used to illuminate an image for projection onto a display screen. However, as with other systems that use laser light, if the laser light is no longer contained, there remains a potential risk for excessive exposure of the user or viewer to the laser light. In laser PTV, containment failure can occur due to a broken or damaged screen. Unaccommodated laser light can directly hit the viewer's eyes or skin, which can result in severe damage to the viewer's eyes and / or skin.

  Thus, systems and methods that facilitate the detection of broken or damaged screens are desirable.

  Embodiments provided herein provide for screen or damage broken in laser PTV due to impact or shock through measurement or monitoring of continuity or resistance of conductive traces or coatings applied to the screen. The present invention relates to a system and method that facilitates detection of a received screen. In one embodiment, a screen damage detection system for laser PTV is formed of a clear, transparent, or translucent conductive material, preferably clear, transparent, applied to a display screen in a snake-like configuration. With transparent or translucent conductive traces. The trace pitch is preferably less than half the size of the hole or crack in the screen to be detected. If the hole or crack in the screen is large enough to open the conductive trace, damage to the screen is detected. The laser enable output signal is used to shut down the laser source to prevent excessive laser light output.

  In another embodiment, the damage detection system preferably comprises a clear, transparent or translucent resistive coating or film, such as a thin metal layer, applied to the screen. Resistance is preferably measured by applying a constant current and measuring the voltage drop across electrodes positioned along the edge of the screen. A microprocessor that records normal resistance in the X and Y axes of an undamaged screen controls a set of switches to sample the X and Y resistances, coating due to cracks or holes in the screen When a resistance change greater than a predetermined value is detected, the laser is disabled or turned off via the laser enable output signal.

  Other objects, systems, methods, features and advantages of the present invention will be or will be apparent to those skilled in the art upon review of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. It will be understood that the particular methods and apparatus are shown for purposes of illustration only and not as limitations. As will be appreciated by those skilled in the art, the principles and features described herein may be used in a wide variety of embodiments.

For example, the present invention provides the following items.
(Item 1)
A screen damage detection system for laser PTV,
Conductive traces disposed on the surface of the PTV display screen;
A damage detection circuit coupled to the conductive trace and configured to detect discontinuities in the conductive trace due to damage of the screen.
(Item 2)
The system of any preceding item, wherein the detected discontinuity is a function of the resistance of the trace.
(Item 3)
A system according to any of the preceding items, wherein the trace is formed from a transparent conductive material.
(Item 4)
A system according to any of the preceding items, wherein the transparent conductive material is indium stannous oxide (ITO).
(Item 5)
The system according to any of the preceding items, wherein the trace is formed in a snake-like configuration.
(Item 6)
A system according to any of the preceding items, wherein the pitch of the trace is less than half the smallest size of holes, cracks or chips in the screen to be detected.
(Item 7)
A system according to any of the preceding items, wherein the circuit is adapted to provide a laser light source shutdown when a discontinuity in the trace is detected.
(Item 8)
The above circuit
A comparator,
A first lead coupled to the first end of the trace and connected to electrical ground;
A second lead coupled to the second end of the trace and the negative input of the comparator;
A pull-up resistor coupled to the second lead and the power source;
A first and a second divider resistor connected in electrical ground and the power source and coupled in parallel with the positive input of the comparator;
The comparator is adapted to compare a reference voltage generated by a split resistor on the positive input of the comparator with a voltage on the negative input of the comparator. The system described in Crab.
(Item 9)
A system according to any of the preceding items, wherein the pull-up resistor is adapted to pull the negative input of the comparator high due to a discontinuity in the trace.
(Item 10)
The comparator is adapted to output an output signal corresponding to a high input on the negative input of the comparator, and the control system is adapted to send a signal to shut down the laser source. The system described in Crab.
(Item 11)
A screen damage detection system for laser PTV,
A resistive film disposed on the surface of the PTV display screen;
A damage detection circuit coupled to the resistive film and configured to detect damage to the screen as a function of a change in resistance of the film.
(Item 12)
A system according to any of the preceding items, wherein the resistive film comprises a thin metal layer.
(Item 13)
A system according to any of the preceding items, wherein the film is formed from a transparent resistive material.
(Item 14)
A system according to any of the preceding items, wherein the circuit detects a change in resistance as a function of a voltage drop across the film.
(Item 15)
A system according to any of the preceding items, wherein the circuit is adapted to provide a laser light source shutdown when a change in resistance is detected.
(Item 16)
The above circuit
A first set of electrodes positioned along a side edge of the screen;
A second set of electrodes positioned along the top and bottom of the screen;
A comparator circuit;
A switch coupled to the comparator circuit;
A current source coupled to the comparator circuit and the switch;
A system according to any of the preceding items, comprising: the first set of electrodes and the second set of electrodes and a first and second set of wire leads coupled to a set of switches. .
(Item 17)
The system according to any of the preceding items, wherein the switch comprises a set of switches.
(Item 18)
The comparator circuit comprises an analog-to-digital converter and a microprocessor, the microprocessor being undamaged along an axis extending between the electrodes of the first and second sets of electrodes. Control the set of switches to sample the resistance along the respective axis to record the normal resistance of the film and detect the resistance change of the film, and the resistance change greater than a predetermined value. The system according to any one of the above items, wherein a disable signal is output when an error is detected.
(Item 19)
A system according to any preceding item, wherein the comparator circuit includes a temperature sensor coupled to the microprocessor.

(Summary)
A system and method that facilitates the detection of broken or damaged screens in laser PTV due to shock or shock through measurement or monitoring of continuity or resistance of conductive traces applied to the screen. In one embodiment, the screen damage detection system comprises a clear conductive trace, preferably applied to a display screen in a snake-like configuration. Damage to the screen is detected when a hole or crack in the screen is large enough to open the conductive trace. In another embodiment, the damage detection system comprises a clear resistive film applied to the screen. Resistance is measured in the X and Y axes to detect changes in coating resistance due to cracks or holes in the screen, and when a change in resistance greater than a predetermined value is detected, the laser via the laser enable output signal Disable.

Details of exemplary embodiments, including manufacturing, structure, and operation, may be gathered in part by a detailed review of the accompanying drawings, wherein like reference numerals refer to like parts. The components in the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the exemplary embodiments. Moreover, all drawings are intended to convey concepts, and relative sizes, shapes, and other detailed attributes may be schematically illustrated rather than literally or accurately.
FIG. 1 is a schematic side view of a laser projection television (PTV). FIG. 2 is a schematic diagram of a control system for laser PTV having an integrated screen damage detection system shown in FIG. FIG. 3 is a schematic plan view of the screen damage detection system. FIG. 4 is a schematic plan view of an alternative embodiment of a screen damage detection system.

  It should be noted that throughout the drawings, for purposes of illustration, similar structural or functional elements are generally indicated by similar reference numerals. It should also be noted that the drawings are only intended to facilitate the description of the preferred embodiments.

(Detailed explanation)
Each of the additional features and teachings disclosed below may be utilized separately or in conjunction with other features and teachings to produce a screen damage detection circuit for a laser projection television. Representative examples of the invention, examples of which utilize many of these features and teachings separately and in combination, will now be described in more detail with reference to the accompanying drawings. This detailed description is merely intended to teach those skilled in the art further details to practice preferred aspects of the teachings of the present invention and is intended to limit the scope of the present invention. Absent. Accordingly, the combinations of features and steps disclosed in the following detailed description may not necessarily be necessary to practice the invention in its broadest sense, but instead are merely representative of the teachings of the invention. Examples are taught to illustrate the examples.

  Furthermore, the various features of the representative examples and the dependent claims are combined in a manner that is specifically and not explicitly recited to provide additional useful embodiments of the teachings of the present invention. Can be. Moreover, all features disclosed in the specification and / or claims are claimed for the purposes of the original disclosure and independent of the components of the features of the embodiments and / or claims. It is expressly noted that for the purpose of limiting the subject matter described, it is intended to be disclosed separately from each other and independently of each other. In addition, an indication of all ranges of values or groups of entities shall include all possible intermediate values or intermediate entities for the purpose of original disclosure and for the purpose of limiting the claimed subject matter. It should also be explicitly noted that it is disclosed.

  Referring to the drawings in detail, FIG. 1 depicts a schematic diagram of a laser projection television (PTV) 10. The PTV 10 includes an image projection engine or system 13 (such as a DLP, LCD or LCOS based projection engine), a projection optical element 16 coupled to the image engine 13, a laser light source 11 coupled to the image engine 13, and a cabinet. 12 includes a cabinet or enclosure 12 that houses a projection screen assembly 14 mounted on the front surface of 12 and a mirror 18 optically coupled to the projection screen assembly 14 and the image projection engine 13 and projection optics 16. . A control module 32 including a logic circuit and other electronic components is mounted in the interior 17 of the cabinet 12.

  Referring to FIG. 2, the PTV 10 preferably includes a control system 30 having a damage detection circuit 100 coupled to the evangelism and race or film 110 formed on the screen 14 and also coupled to the control module 32. Yes. The control module 32 is also coupled to a television on-screen display (OSD) controller 42 and the laser light source 11. Both the OSD controller 42 and the laser light source 11 are coupled to a television projection engine 13, which is operatively coupled to the screen 14.

  The control module 32 preferably includes a microprocessor 34, a non-volatile memory 36, and system software 38 stored in the memory 36. The software 38 is preferably a set of instructions used to control the overall operation of the television 10, and in particular to shut down the operation of the laser light source 11 in response to a laser enable signal received from the damage detection circuit 100. Is included.

The damage detection circuit 110 detects a screen that has been damaged due to an impact or shock through measurement of the continuity or resistance of a conductive trace or coating 112 applied to the screen 14. In one embodiment, as depicted in FIG. 3, damage detection system 100 preferably comprises indium stannous oxide (ITO) or other clear, transparent, or translucent conductive material, preferably A clear, transparent, or translucent conductive trace 112 is applied to the screen 14 in a snake-like configuration. The pitch of the traces 112 is preferably less than half the size of the holes or cracks in the screen 14 to be detected. Damage detection circuit 110 includes a first lead 114 coupled to a first end of trace 112 and connected to electrical ground 116. The second lead 113 coupled to the other end of the trace 112, a pull-up resistor R ₃ to Vcc, is connected to the negative input of comparator 118. Comparator 118 compares the reference voltage at the positive input of comparator 118 (generated by dividing resistors R ₁ and R ₂ ) with the voltage at the negative input of comparator 118. If a hole or crack in the screen 14 is large enough to open the conductive trace 112, damage to the screen 14 is detected. In a state where trace 112 is open, the pull-up resistor R ₃ is pulled high the negative input of the comparator 118, resulting in an output signal of the comparator 118 is low. The output laser enable signal is received and monitored by the control module 32, which shuts down the laser light source 11 and removes power to the laser light source, or a laser driver circuit when a low power laser enable signal is received. Disable to prevent excessive light output.

  In another embodiment, as depicted in FIG. 4, the damage detection system 200 is a clear, transparent, or translucent resistive coating or film, such as a thin metal layer, applied to the screen 14. 212 is provided. The damage detection circuit 210 includes an electrode 213 and an electrode 215 positioned adjacent to the end of the screen 14. Wire leads 211, 214, 216 and 218 are attached to electrode 213 and electrode 215 and the change in resistance of coating 212 is measured in the X and Y axes to detect damaged screen 14. Make it possible. A set of switches 220 connects the X or Y electrode 213 and electrode 215 to the comparator circuit 230 to measure the resistance of the coating 212. Resistance is measured by applying a constant current through an appropriate current source 222 and measuring the voltage drop across the electrodes using an analog to digital converter 232 and a microprocessor 236. In order to detect changes in the coating 212 resistance due to cracks or holes in the screen 14, the microprocessor 236 controls a set of switches 220 to sample the resistance in the X and Y axes and sampled resistance. Is compared to the stored resistance or the recorded normal resistance in the X and Y axes of the undamaged screen 14. Microprocessor 236 disables or shuts down the laser enable output signal when a change in resistance greater than a predetermined value is detected. The output laser enable signal is received and monitored by the control module 32, and the control module 32 shuts down the laser light source 11 and turns off power to the laser light source when a resistance change greater than a predetermined value is detected. Or, disable the laser driver circuit to prevent excessive light output.

  A temperature sensor 234 can be connected to the microprocessor 236 to compensate for changes in the resistance of the screen coating 212 due to ambient temperature changes.

  In the foregoing specification, specific exemplary embodiments have been described. It will be apparent, however, that various modifications and changes can be made to the present invention without departing from the broader spirit and scope of the invention. For example, the reader is aware that the specific order and combination of process operations shown in the process flow diagrams described herein are exemplary only, unless otherwise stated, and that the invention is different or additional in process. It should be understood that operations may be performed using different combinations or sequences of operations or processes. As another example, each feature of one embodiment can be mixed and matched with other features shown in other embodiments. Features and processes known to those skilled in the art can be incorporated as well, if desired. In addition, and obviously, features can be added or deleted as needed. Accordingly, the invention should not be limited except in light of the attached claims and their equivalents.

10 Laser projection television (PTV)
11 Laser source 12 Cabinet or enclosure 13 Image projection engine or system 14 Projection screen assembly 16 Projection optics 17 Interior of cabinet 18 Mirror 32 Control module

Claims (19)

A screen damage detection system for laser PTV,
Conductive traces disposed on the surface of the PTV display screen;
A damage detection circuit coupled to the conductive trace and configured to detect discontinuities in the conductive trace due to damage of the screen.   The system of claim 1, wherein the detected discontinuity is a function of the resistance of the trace.   The system of claim 1, wherein the trace is formed from a transparent conductive material.   The system of claim 3, wherein the transparent conductive material is indium stannous oxide (ITO).   The system of claim 1, wherein the trace is formed in a snake-like configuration.   The system of claim 1, wherein the pitch of the trace is less than half the smallest size of a hole, crack or tip in the screen to be detected.   The system of claim 1, wherein the circuit is adapted to provide a laser light source shutdown when a discontinuity in the trace is detected. The circuit is
A comparator,
A first lead coupled to the first end of the trace and connected to electrical ground;
A second lead coupled to the second end of the trace and the negative input of the comparator;
A pull-up resistor coupled to the second lead and the power source;
A first and a second divider resistor connected in electrical ground and the power source and coupled in parallel with the positive input of the comparator;
The comparator according to claim 7, wherein the comparator is adapted to compare a reference voltage generated by a split resistor on the positive input of the comparator with a voltage on the negative input of the comparator. The system described.   The system of claim 8, wherein the pull-up resistor is adapted to pull the negative input of the comparator high due to a discontinuity in the trace.   9. The comparator according to claim 8, wherein the comparator is adapted to output an output signal corresponding to a high input on the negative input of the comparator to signal the control system to shut down the laser light source. The described system. A screen damage detection system for laser PTV,
A resistive film disposed on the surface of the PTV display screen;
A damage detection circuit coupled to the resistive film and configured to detect damage to the screen as a function of a change in resistance of the film.   The system of claim 11, wherein the resistive film comprises a thin metal layer.   The system of claim 11, wherein the film is formed from a transparent resistive material.   The system of claim 11, wherein the circuit detects a change in resistance as a function of a voltage drop across the film.   The system of claim 11, wherein the circuit is adapted to provide a laser light source shutdown when a change in resistance is detected. The circuit is
A first set of electrodes positioned along a side edge of the screen;
A second set of electrodes positioned along the top and bottom of the screen;
A comparator circuit;
A switch coupled to the comparator circuit;
A current source coupled to the comparator circuit and the switch;
16. The system of claim 15, comprising: the first set of electrodes and the second set of electrodes and first and second sets of wire leads coupled to a set of switches.   The system of claim 16, wherein the switch comprises a set of switches.   The comparator circuit comprises an analog-to-digital converter and a microprocessor, the microprocessor being undamaged along an axis extending between the electrodes of the first and second sets of electrodes. Control the set of switches to sample the resistance along the respective axis to record the normal resistance of the film and detect the resistance change of the film, and the resistance change greater than a predetermined value The system of claim 17, wherein a disable signal is output when an error is detected.   The system of claim 18, wherein the comparator circuit includes a temperature sensor coupled to the microprocessor.

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