WO2008102050A1 - Information board and its control unit - Google Patents

Information board and its control unit Download PDF

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Publication number
WO2008102050A1
WO2008102050A1 PCT/FI2007/050090 FI2007050090W WO2008102050A1 WO 2008102050 A1 WO2008102050 A1 WO 2008102050A1 FI 2007050090 W FI2007050090 W FI 2007050090W WO 2008102050 A1 WO2008102050 A1 WO 2008102050A1
Authority
WO
WIPO (PCT)
Prior art keywords
information board
temperature
voltage
power supply
control unit
Prior art date
Application number
PCT/FI2007/050090
Other languages
French (fr)
Inventor
Pasi Karppanen
Original Assignee
Symbicon Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Symbicon Oy filed Critical Symbicon Oy
Priority to PCT/FI2007/050090 priority Critical patent/WO2008102050A1/en
Publication of WO2008102050A1 publication Critical patent/WO2008102050A1/en

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/13306—Circuit arrangements or driving methods for the control of single liquid crystal cells
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
    • G06F1/16—Constructional details or arrangements
    • G06F1/20—Cooling means
    • G06F1/206—Cooling means comprising thermal management
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/041—Temperature compensation
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/021—Power management, e.g. power saving
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/04—Display protection
    • G09G2330/045—Protection against panel overheating
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3648—Control of matrices with row and column drivers using an active matrix

Definitions

  • the invention relates to an electronic information board and its control unit. In addition, the invention relates to a control method of the information board.
  • the display of an electronic information board can be implemented by applying any prior art display device technology.
  • the most advantageous display technology for display devices of a few square metres and less is the TFT
  • LCD technology Thin Film Transistor - Liquid Crystal Display
  • plasma displays can be used in information boards.
  • TFT LCD displays are used in the implementation of public electronic information boards.
  • the problem is that when used in warm environments, the temperatures of the display devices easily rise too high. On the other hand, in cold environments there is the danger that the temperatures of the display devices fall too low. In both situations it is important that the temperatures at different points inside the display device can be stabilized to the desired temperature. Then the display device will function, and local temperatures do not cause exceeding of the specifications given to the display element.
  • the warming of the display in cold conditions has often been solved by a transparent warming resistor fastened to the transparent window of the device.
  • the problem is the high price of components, because the manufacture of a transparent warming element requires special solutions.
  • a transparent warming element fastened to the glass only warms the display on the front side, and the fluorescent tubes inside the display operate in consid- erably colder conditions than the TFT LCD matrix.
  • the efficiency of fluorescent tubes used in connection with display devices generally weakens radically when the temperature falls, and therefore the brightness of the display may be significantly reduced in cold conditions.
  • the operating life of electronic information boards remains shorter than normal, or they are unnecessarily damaged.
  • the LCD matrix of TFT LCD display elements be- comes inoperative already at the temperature of 70°C. If the temperatures cannot be stabilized in different parts of the display element, the temperatures of the upper parts set a limit to the highest possible operating temperature allowed for the whole display device. The probability of the electronics of the device getting damaged in the hottest parts of the device also increases significantly. Because of the problems related to the temperature control of electronic information boards, they have been poorly suited for use in variable conditions, such as outdoors, where the differences of temperature at day and night and especially at different times of the year are substantial. Because of this, electronic information boards have seldom been used outdoors, but the conventional illuminated boards containing a paper poster have been used instead.
  • the energy supply of the separate, electronic subcomponents included in the electronic information board is managed by component-specific power units. If the operating voltage required by the components varies, this often results in the use of many separate voltage sources in one infor- mation board. A structure like that is expensive, and additionally the waste heat caused by a number of voltage sources warms the information board unnecessarily. This also contributes to the temperature problems described above.
  • the objectives of the invention are achieved by a device arrangement in which the operation of the information board is controlled by a control unit, which prevents the functions of the information board if the temperature measured from the information board is not within the set limits.
  • a plurality of different operating voltages is also available to the control unit, whereby the use of many separate voltage sources giving only one voltage each is avoided.
  • the control unit according to the invention provides the advantage that the information board is not damaged because of too high or too low an operating temperature.
  • the invention has the advantage that the information board can be set to operate only in suitable operating temperatures.
  • the invention has the advantage that if the use of the information board has been prevented because of an unsuitable temperature, the control unit starts the information board again when the temperature returns to the allowed range.
  • Yet another advantage of the invention is that the operating voltages required in the information board are obtained from the control unit, and no separate, component-specific voltage sources are required.
  • the information board according to the invention is characterized in that it comprises a control unit, which comprises
  • the supply of power to the components of the information board is switched off if the temperature of the information board is not in the allowed temperature range.
  • Power supply to the information board is managed by a control unit, from which a plurality of operating voltages required by the information board can be obtained.
  • the switching on of the operating voltages is dependent on the temperature measured from the information board.
  • the control unit only begins the power-up of the information board or maintains its operation in a situation in which the measured operation temperature is in the specified range of use for the information board. If the operating temperature of the information board differs from the specified operating temperature, the control unit supplies the operating voltage only to the fans. The operating voltage is not supplied to the other electrical components of the information board, which prevents the operation or starting of the information board. If the control unit has powered down the operation of the information board because of an unfavourable operating temperature, the control unit will switch on the required operation volt- ages again to all the electrical components of the information board when the operating temperature returns back to the allowed range of operating temperature.
  • Figure 1 shows an information board according to the invention by way of example
  • FIG. 2 shows the functional main parts of the control unit according to the invention by way of example
  • Figure 3 shows, as an exemplary flow chart, the main steps of the control method of the information board according to the invention.
  • an electronic information board 10 is shown as a perspective drawing viewed obliquely from behind.
  • Number 61 indicates a PC (Personal Computer), which controls the electrical components of the information board 10 and its display element 30, which is preferably a TFT-LCD element.
  • Number 62 indicates a control unit according to the invention, and number 63 indicates a direct voltage source, from which the control unit 62 according to the invention obtains the direct voltage needed for its operation.
  • the size of the direct voltage obtained from the direct voltage source 63 can be +24 V, for example.
  • a display casing has been fastened to the body 40 of the information board 10, having a transparent front plate, behind which the display element 30 is located.
  • the transparent front plate has been fastened in such a way that the edge parts and the rear wall of the front plate form a closed display casing.
  • the back cover of the information board 10 the rear wall of the device casing 60 and the rear wall of the fan casing 70 are not shown in Fig. 1.
  • the display element 30 and the display casing protecting it are on the back side of the information board 10, which is not seen in Fig. 1.
  • circulation fans 72 which provide a closed circulation of cooling air through the fan casing 70, the cross-flow cell 80, the device casing 60 and the other structural parts of the information board 10.
  • the walls of the device, display and fan casings are airtight. Thus it has been ensured that the cooling air of the device and display casings circulates all the time in an internal circulation closed from the outdoor air.
  • the operation of the circulation fans is preferably allowed or prevented by a control unit 62 according to the invention.
  • a circulating air flow passing through the device and display casing is formed in order to keep the tempera- ture of the casings within the desired limits.
  • the circulating air flow flushes the surface of the parts that are warming up, such as the surface of the display element 30, whereby the heat is effectively transferred from the warming components directly to the air flow.
  • the device and display casings are equipped with temperature measurement sensors (no. 621 in Fig. 2), which are connected to the control unit 62 in the device casing of the information board 10.
  • the control unit 62 adjusts the operation of the circulation fans 72 on the basis of the measured temperatures in accordance with predetermined control logic. The efficiency of the fans can be adjusted within the limits of 15 - 100% compared to the maximum efficiency.
  • the circulation of the inner cooling air achieved by the circulation fans 72 By means of the circulation of the inner cooling air achieved by the circulation fans 72, the temperatures of the inner parts of the display casing and the device casing can be stabilized, and the heat can be efficiently transferred out from the inside of the casings. Due to the inner circulation of air, the heat produced by a spotlike heat source, such as a power supply, can be distributed efficiently and evenly in the whole inner space of the casing.
  • the circulation of inside air enables cooling the edges of the display element especially in the upper parts of the display casing. This is important especially in TFT LCD displays with regard to the cooling of the control circuits of the display.
  • the control circuits are located close to the outer edge of the display element. Without efficient cooling, the temperatures of the control circuits would rise higher than in other parts of the TFT LCD display element 30.
  • cooling fans 76 fastened to the rear wall of the display casing, by which a forced air flow is formed through the cross-flow cell 80 along the horizontal second flow channels.
  • ventilation slots 78 in both side walls of the information board, enabling the access of cool outside air to the cross-flow cell, and the removal of the air warmed up in the cell back to the outside air.
  • the ventilation slots can be equipped with filters (not shown in Fig. 1) in order to prevent the access of impurities to the cross-flow cell.
  • the operation of the cooling fans is controlled by the control unit 62 according to the invention, which is located in the device casing.
  • the fan housing 70 also includes an electrically operated heating resistor (not shown in
  • Fig. 1 by which the air flowing through the display and device casing can be warmed, when required.
  • the operation of the heating resistor is controlled by a thermostat in the device casing.
  • This preferred embodiment of the invention is suitable for use in cold conditions, in which the heat produced by the electrical components of the information board 10 is not sufficient for achieving a suitable operating temperature.
  • the display element 30 and the electronic devices in the device casing warm up, whereby the temperature of the device casing 60 and the display casing rise.
  • the ambient conditions such as the temperature of the location of the information board and possible sunshine have an effect on the warming up of the information board 10.
  • the operating voltages required by different electrical components of the information board 10 are preferably generated in a centralized manner.
  • an ex- emplary voltage source producing a direct voltage of +24 V is indicated by number 63.
  • the voltage source 63 can be fed by an alternating voltage obtained from a conventional low-voltage network, for example, which is converted to the desired direct voltage by the voltage source 63.
  • the control unit of the information board according to the invention is indicated by number 62.
  • Fig. 2 shows the functional main parts of the control unit 62 according to the invention, which is used to allow or prevent the operation of the TFT LCD information board 10.
  • Number 63 indicates the exemplary direct voltage source used in the information board 10. In the example of Fig. 2, it produces a direct voltage of +24 V, which is supplied through the connection 631 to the control unit 62 according to the invention.
  • the direct voltage is supplied to the switching unit 620 and the power supply of the fans included in the power supply 623 through a fixed connection 632.
  • the direct voltage to the power supplies of the LCD display, the backlight and the PC which are also included in the power supply 623, is supplied through an openable connection 633.
  • the control unit 62 preferably comprises a switching unit 620, a power supply 623 for producing operating voltages to the electrical components of the information board, and an electronic switching unit 622, by which a direct voltage of +24 V is switched to the input of the power supply 623 of the control unit 62.
  • the operating voltages to the TFT LCD element 640, the backlight 650 and the PC 660 controlling the operation of the information board are obtained from the power supply 623.
  • the operating voltages obtained from the power sup- ply 623 may vary in their magnitude and current supply properties. Due to this arrangement, it is not necessary to install a separate voltage source for each electrical component in the information board 10.
  • the power feed of the switching unit 620 according to the invention which is included in the control unit 62, is obtained directly from the direct voltage source 63 through the fixed connection 632.
  • the same fixed connection 632 is also used for supplying power to the unit belonging to the power supply 623, which feeds the power 630 to the fans of the information board 10. Because the power supply connection 632 is fixed, it supplies power to the switching unit 620 and the fans always when the operating switch of the information board 10 is in the "CLOSED" position.
  • Input 661 connects the control unit 62 to the PC controlling the other operations of the information board 10, number 61. Through this input 661 , the control unit 62 gets the information on whether the TFT LCD display of the information board 10 is in operation or not.
  • the switching unit 620 controls at least one electronic switch arrangement 622, which has been arranged to open (“OPEN") or close (“CLOSE") the connection 633.
  • the connection 633 is opened or closed on the basis of the measurement information obtained from the temperature sensor 621. If the measured temperature is higher than the allowed upper limit or lower than the allowed lower limit of the temperature, the switching unit 620 switches off the connection 633 by opening the switch arrangement 622. Then the voltage of the input of the power supply 623 falls off, and as a result the voltage outputs of the power, supply 623 to the LCD display, backlight and the PC, 640-660, are set to zero potential. All operating voltages of the electrical components of the information board 10 fall off, except the switching unit 620 and the power supply of the fans.
  • the switching unit 620 remains in operation even in this exceptional situation, because it still gets its operating voltage from the direct voltage source 63 through the fixed connection 632. Because of this, the temperature measurement of the information board 10 can be active even when other operation of the information board 10 has been prevented because of the detected temperature problem. If the temperature returns between the specified upper and lower limits, the switching unit 620 closes the connection 633 by means of the electronic switch arrangement 622. As a result of this, the power supply 623 is switched on, and the operating voltages 640-660 are again switched on to the different electrical components of the information board.
  • the power-up of the information board 10 is preferably controlled by a PC, number 61.
  • Fig. 3 is an exemplary flow chart of the main steps of the operation control of an information board 10 according to the invention.
  • the main switch of the information board is switched to the position "CLOSED". This measure switches on the voltage feed to the direct voltage source 63 of the information board 10. Then the voltage feed is also switched on to the switching unit 620, which is included in the control unit 62.
  • the control unit 62 starts the temperature measurements and compares the measured temperature to the limit values set for the information board 10, step 31. If the temperature is not between the allowed upper and lower limits of the temperature, the power-up of the information board 10 is prevented in step 33. In practice, this is done by keeping the electronic switch arrangement 622 in the "OPEN" state. The "OPEN" state can be changed, if the temperature measured from the information board 10 returns to the allowed range of temperatures.
  • step 32 If it is found in step 31 that the measured temperature is in the allowed range of temperatures, in step 32 the fans 72, 76 of the information board 10 are started first.
  • step 34 it is checked in step 34 whether the information board 10 is in operation or not. If a power-up operation is to be performed on the information board, it has not been started yet. In that case, the next step is branching to step 35, in which the PC, number 61 , controlling the information board 10, is started. After this, the PC begins the power-up of the LCD display in step 36. When the power-up of the LCD display has been carried out after step 36, the process returns to step 31 , and the temperature of the information board 10 is measured again. If the measured temperature is in the allowed range of temperatures, the process moves to step 32, in which the control of the fans 72 and 76 is maintained. After this, it is found in step 34 that the information board 10 is in operation, and the process returns to step 31 again. If the temperature measured from the information board remains in the allowed range of temperatures, the steps 31 , 32 and 34 are repeated, until the main switch of the information board 10 is moved to the position "OPEN".
  • step 31 If it is found in step 31 that the temperature of the information board 10 has moved to the non-allowed temperature range, in this situation the operation branches to step 33. Then a part of the operations of the information board 10 are powered down by switching off voltage feed to the power supply 623 by an electronic switch arrangement 622. However, the fans of the information board preferably remain in operation. Their blow efficiency can be set to 10 - 100% of the maximum blow efficiency. Also in this situation, the control unit 62 measures the temperature inside the information board 10 if the operating switch of the information board is still in the "CLOSED" position. If the temperature returns to the allowed temperature range, the control unit 62 switches on the voltage feed to the power supply 623 again, whereby the power-up of the information board 10 starts according to the process described above.

Abstract

The invention relates to an electronic information board, a control unit (62) of the information board and a temperature-based control method of the information board. In the information board according to the invention, the operating voltages (630, 640, 650, 660) required by it are generated in a centralized manner in the power supply (623) of the control unit (62). The control unit also includes a switching unit (620), which switches the input voltage of the power supply (623) on or off on the basis of the temperature measured inside the information board.

Description

Information Board and its Control Unit
The invention relates to an electronic information board and its control unit. In addition, the invention relates to a control method of the information board.
The display of an electronic information board can be implemented by applying any prior art display device technology. For the present, the most advantageous display technology for display devices of a few square metres and less is the TFT
LCD technology (Thin Film Transistor - Liquid Crystal Display), which provides the advantages of a large viewing angle, a short response time, a good contrast and the reliability of the display. In addition to TFT LCD displays, other electronic dis- play solutions, such as plasma displays, can be used in information boards.
TFT LCD displays are used in the implementation of public electronic information boards. The problem is that when used in warm environments, the temperatures of the display devices easily rise too high. On the other hand, in cold environments there is the danger that the temperatures of the display devices fall too low. In both situations it is important that the temperatures at different points inside the display device can be stabilized to the desired temperature. Then the display device will function, and local temperatures do not cause exceeding of the specifications given to the display element.
In the present devices, the warming of the display in cold conditions has often been solved by a transparent warming resistor fastened to the transparent window of the device. In this solution, the problem is the high price of components, because the manufacture of a transparent warming element requires special solutions. A transparent warming element fastened to the glass only warms the display on the front side, and the fluorescent tubes inside the display operate in consid- erably colder conditions than the TFT LCD matrix. The efficiency of fluorescent tubes used in connection with display devices generally weakens radically when the temperature falls, and therefore the brightness of the display may be significantly reduced in cold conditions.
An alternative solution for warming the display device is to warm it from behind by various warming resistors and corresponding arrangements. These solutions, again, entail the problem that the TFT LCD matrix on the front surface of the display may then operate in too cold conditions, whereby the response time of the display increases. In the worst case, the temperature of the TFT LCD matrix may fall under the storage temperature allowed for the display. With regard to the cooling of information screens, the prior art solutions have the drawback that the displays are cooled by forced convection only from behind. However, the display elements produce heat in every direction. Most of the heat in plasma displays is generated on the side of the visible surface of the display. Therefore, the present display casings having a transparent window result in a significant rise of temperature in the upper parts of the display especially on the visible side of the display. In addition, the present solutions have the problem of temperature control caused by the integration of the electronics controlling the display and the actual display element. As a result, there are often situations in which heat is cumulated in certain parts of the device when components that are warming up increase the temperatures of each other.
Because of the inadequate cooling and warming solutions, the operating life of electronic information boards remains shorter than normal, or they are unnecessarily damaged. For example, the LCD matrix of TFT LCD display elements be- comes inoperative already at the temperature of 70°C. If the temperatures cannot be stabilized in different parts of the display element, the temperatures of the upper parts set a limit to the highest possible operating temperature allowed for the whole display device. The probability of the electronics of the device getting damaged in the hottest parts of the device also increases significantly. Because of the problems related to the temperature control of electronic information boards, they have been poorly suited for use in variable conditions, such as outdoors, where the differences of temperature at day and night and especially at different times of the year are substantial. Because of this, electronic information boards have seldom been used outdoors, but the conventional illuminated boards containing a paper poster have been used instead.
In the prior art information board, the energy supply of the separate, electronic subcomponents included in the electronic information board is managed by component-specific power units. If the operating voltage required by the components varies, this often results in the use of many separate voltage sources in one infor- mation board. A structure like that is expensive, and additionally the waste heat caused by a number of voltage sources warms the information board unnecessarily. This also contributes to the temperature problems described above.
It is an objective of the invention to provide a control arrangement for an electronic information board, by which the drawbacks and disadvantages related to the power supply and temperature control of prior art electronic information boards can be significantly reduced. The objectives of the invention are achieved by a device arrangement in which the operation of the information board is controlled by a control unit, which prevents the functions of the information board if the temperature measured from the information board is not within the set limits. A plurality of different operating voltages is also available to the control unit, whereby the use of many separate voltage sources giving only one voltage each is avoided.
The control unit according to the invention provides the advantage that the information board is not damaged because of too high or too low an operating temperature.
In addition, the invention has the advantage that the information board can be set to operate only in suitable operating temperatures.
Moreover, the invention has the advantage that if the use of the information board has been prevented because of an unsuitable temperature, the control unit starts the information board again when the temperature returns to the allowed range.
Yet another advantage of the invention is that the operating voltages required in the information board are obtained from the control unit, and no separate, component-specific voltage sources are required.
The control unit of an electronic information board according to the invention is characterized in that it comprises
- a direct voltage input
- a power supply, which comprises a plurality of voltage outputs
- an openable electrical connection between the direct voltage input and the power supply
- means for measuring the temperature of the information board, and
- means for setting the voltage outputs of the power supply to the "ON" or "OFF" state on the basis of the temperature measured from the information board.
The information board according to the invention is characterized in that it comprises a control unit, which comprises
- a direct voltage input - a power supply, which comprises a plurality of voltage outputs
- an openable electrical connection between the direct voltage input and the power supply
- means for measuring the temperature of the information board, and
- means for setting the voltage outputs of the power supply to the "ON" or "OFF" state on the basis of the temperature measured from the information board.
The method for controlling an electronic information board according to the invention is characterized in that in the method
- the temperature of the information board is measured continuously
- a comparison is made to determine whether the measured temperature is in the temperature range allowed for the information board
- the supply of power to the components of the information board is switched off if the temperature of the information board is not in the allowed temperature range.
- the supply of power to the components of the information board is switched on again if the measured temperature is found to have returned to the allowed temperature range.
Some preferred embodiments of the invention are presented in the dependent claims.
The basic idea of the invention is the following: Power supply to the information board is managed by a control unit, from which a plurality of operating voltages required by the information board can be obtained. The switching on of the operating voltages is dependent on the temperature measured from the information board. The control unit only begins the power-up of the information board or maintains its operation in a situation in which the measured operation temperature is in the specified range of use for the information board. If the operating temperature of the information board differs from the specified operating temperature, the control unit supplies the operating voltage only to the fans. The operating voltage is not supplied to the other electrical components of the information board, which prevents the operation or starting of the information board. If the control unit has powered down the operation of the information board because of an unfavourable operating temperature, the control unit will switch on the required operation volt- ages again to all the electrical components of the information board when the operating temperature returns back to the allowed range of operating temperature.
In the following, the invention will be described in more detail. Reference will be made to the accompanying drawings, in which
Figure 1 shows an information board according to the invention by way of example,
Figure 2 shows the functional main parts of the control unit according to the invention by way of example, and
Figure 3 shows, as an exemplary flow chart, the main steps of the control method of the information board according to the invention.
In Fig. 1 , an electronic information board 10 according to the invention is shown as a perspective drawing viewed obliquely from behind. Number 61 indicates a PC (Personal Computer), which controls the electrical components of the information board 10 and its display element 30, which is preferably a TFT-LCD element. Number 62 indicates a control unit according to the invention, and number 63 indicates a direct voltage source, from which the control unit 62 according to the invention obtains the direct voltage needed for its operation. The size of the direct voltage obtained from the direct voltage source 63 can be +24 V, for example.
A display casing has been fastened to the body 40 of the information board 10, having a transparent front plate, behind which the display element 30 is located. The transparent front plate has been fastened in such a way that the edge parts and the rear wall of the front plate form a closed display casing. In order to emphasize the structures that are important with regard to the temperature control of the device, the back cover of the information board 10, the rear wall of the device casing 60 and the rear wall of the fan casing 70 are not shown in Fig. 1. The display element 30 and the display casing protecting it are on the back side of the information board 10, which is not seen in Fig. 1.
Inside the fan casing 70 included in the information board 10 there are circulation fans 72, which provide a closed circulation of cooling air through the fan casing 70, the cross-flow cell 80, the device casing 60 and the other structural parts of the information board 10. When the circulation fans are in operation, air flows from the fan housing through the flow aperture 64c to the cross-flow cell 80, from the cross- flow cell through the flow aperture 64d to the device casing 60, from the device casing through the flow aperture 64a to the upper part of the information board 10, and through the flow aperture 64b on the lower part of the information board 10 back to the fan housing, after which a new cycle starts. The walls of the device, display and fan casings are airtight. Thus it has been ensured that the cooling air of the device and display casings circulates all the time in an internal circulation closed from the outdoor air. The operation of the circulation fans is preferably allowed or prevented by a control unit 62 according to the invention.
In the information board 10 according to the invention, a circulating air flow passing through the device and display casing is formed in order to keep the tempera- ture of the casings within the desired limits. The circulating air flow flushes the surface of the parts that are warming up, such as the surface of the display element 30, whereby the heat is effectively transferred from the warming components directly to the air flow. The device and display casings are equipped with temperature measurement sensors (no. 621 in Fig. 2), which are connected to the control unit 62 in the device casing of the information board 10. The control unit 62 adjusts the operation of the circulation fans 72 on the basis of the measured temperatures in accordance with predetermined control logic. The efficiency of the fans can be adjusted within the limits of 15 - 100% compared to the maximum efficiency. By means of the circulation of the inner cooling air achieved by the circulation fans 72, the temperatures of the inner parts of the display casing and the device casing can be stabilized, and the heat can be efficiently transferred out from the inside of the casings. Due to the inner circulation of air, the heat produced by a spotlike heat source, such as a power supply, can be distributed efficiently and evenly in the whole inner space of the casing. The circulation of inside air enables cooling the edges of the display element especially in the upper parts of the display casing. This is important especially in TFT LCD displays with regard to the cooling of the control circuits of the display. The control circuits are located close to the outer edge of the display element. Without efficient cooling, the temperatures of the control circuits would rise higher than in other parts of the TFT LCD display element 30.
There are cooling fans 76 fastened to the rear wall of the display casing, by which a forced air flow is formed through the cross-flow cell 80 along the horizontal second flow channels. For enabling the air flow, there are ventilation slots 78 in both side walls of the information board, enabling the access of cool outside air to the cross-flow cell, and the removal of the air warmed up in the cell back to the outside air. When required, the ventilation slots can be equipped with filters (not shown in Fig. 1) in order to prevent the access of impurities to the cross-flow cell. The operation of the cooling fans is controlled by the control unit 62 according to the invention, which is located in the device casing.
In a preferred embodiment of the information board according to the invention, the fan housing 70 also includes an electrically operated heating resistor (not shown in
Fig. 1), by which the air flowing through the display and device casing can be warmed, when required. The operation of the heating resistor is controlled by a thermostat in the device casing. This preferred embodiment of the invention is suitable for use in cold conditions, in which the heat produced by the electrical components of the information board 10 is not sufficient for achieving a suitable operating temperature.
When the information board 10 is in operation, the display element 30 and the electronic devices in the device casing warm up, whereby the temperature of the device casing 60 and the display casing rise. In addition to the heat production of the power supplies 63 and the electrical components, the ambient conditions, such as the temperature of the location of the information board and possible sunshine have an effect on the warming up of the information board 10.
The operating voltages required by different electrical components of the information board 10 are preferably generated in a centralized manner. In Fig. 1 , an ex- emplary voltage source producing a direct voltage of +24 V is indicated by number 63. The voltage source 63 can be fed by an alternating voltage obtained from a conventional low-voltage network, for example, which is converted to the desired direct voltage by the voltage source 63. The control unit of the information board according to the invention is indicated by number 62.
Fig. 2 shows the functional main parts of the control unit 62 according to the invention, which is used to allow or prevent the operation of the TFT LCD information board 10.
Number 63 indicates the exemplary direct voltage source used in the information board 10. In the example of Fig. 2, it produces a direct voltage of +24 V, which is supplied through the connection 631 to the control unit 62 according to the invention. In the control unit 62, the direct voltage is supplied to the switching unit 620 and the power supply of the fans included in the power supply 623 through a fixed connection 632. On the other hand, the direct voltage to the power supplies of the LCD display, the backlight and the PC, which are also included in the power supply 623, is supplied through an openable connection 633.
The control unit 62 preferably comprises a switching unit 620, a power supply 623 for producing operating voltages to the electrical components of the information board, and an electronic switching unit 622, by which a direct voltage of +24 V is switched to the input of the power supply 623 of the control unit 62. In the example of Fig. 2, the operating voltages to the TFT LCD element 640, the backlight 650 and the PC 660 controlling the operation of the information board are obtained from the power supply 623. The operating voltages obtained from the power sup- ply 623 may vary in their magnitude and current supply properties. Due to this arrangement, it is not necessary to install a separate voltage source for each electrical component in the information board 10.
The power feed of the switching unit 620 according to the invention, which is included in the control unit 62, is obtained directly from the direct voltage source 63 through the fixed connection 632. The same fixed connection 632 is also used for supplying power to the unit belonging to the power supply 623, which feeds the power 630 to the fans of the information board 10. Because the power supply connection 632 is fixed, it supplies power to the switching unit 620 and the fans always when the operating switch of the information board 10 is in the "CLOSED" position.
Input 661 connects the control unit 62 to the PC controlling the other operations of the information board 10, number 61. Through this input 661 , the control unit 62 gets the information on whether the TFT LCD display of the information board 10 is in operation or not.
Connected to the switching unit 620, there are one or more temperature sensors 621 , by which the temperature is preferably measured in different parts of the information board 10. The switching unit 620 controls at least one electronic switch arrangement 622, which has been arranged to open ("OPEN") or close ("CLOSE") the connection 633. The connection 633 is opened or closed on the basis of the measurement information obtained from the temperature sensor 621. If the measured temperature is higher than the allowed upper limit or lower than the allowed lower limit of the temperature, the switching unit 620 switches off the connection 633 by opening the switch arrangement 622. Then the voltage of the input of the power supply 623 falls off, and as a result the voltage outputs of the power, supply 623 to the LCD display, backlight and the PC, 640-660, are set to zero potential. All operating voltages of the electrical components of the information board 10 fall off, except the switching unit 620 and the power supply of the fans.
The switching unit 620 remains in operation even in this exceptional situation, because it still gets its operating voltage from the direct voltage source 63 through the fixed connection 632. Because of this, the temperature measurement of the information board 10 can be active even when other operation of the information board 10 has been prevented because of the detected temperature problem. If the temperature returns between the specified upper and lower limits, the switching unit 620 closes the connection 633 by means of the electronic switch arrangement 622. As a result of this, the power supply 623 is switched on, and the operating voltages 640-660 are again switched on to the different electrical components of the information board. The power-up of the information board 10 is preferably controlled by a PC, number 61.
Fig. 3 is an exemplary flow chart of the main steps of the operation control of an information board 10 according to the invention. In step 30, the main switch of the information board is switched to the position "CLOSED". This measure switches on the voltage feed to the direct voltage source 63 of the information board 10. Then the voltage feed is also switched on to the switching unit 620, which is included in the control unit 62. Immediately after switching on the operating voltage, the control unit 62 starts the temperature measurements and compares the measured temperature to the limit values set for the information board 10, step 31. If the temperature is not between the allowed upper and lower limits of the temperature, the power-up of the information board 10 is prevented in step 33. In practice, this is done by keeping the electronic switch arrangement 622 in the "OPEN" state. The "OPEN" state can be changed, if the temperature measured from the information board 10 returns to the allowed range of temperatures.
If it is found in step 31 that the measured temperature is in the allowed range of temperatures, in step 32 the fans 72, 76 of the information board 10 are started first.
After this, it is checked in step 34 whether the information board 10 is in operation or not. If a power-up operation is to be performed on the information board, it has not been started yet. In that case, the next step is branching to step 35, in which the PC, number 61 , controlling the information board 10, is started. After this, the PC begins the power-up of the LCD display in step 36. When the power-up of the LCD display has been carried out after step 36, the process returns to step 31 , and the temperature of the information board 10 is measured again. If the measured temperature is in the allowed range of temperatures, the process moves to step 32, in which the control of the fans 72 and 76 is maintained. After this, it is found in step 34 that the information board 10 is in operation, and the process returns to step 31 again. If the temperature measured from the information board remains in the allowed range of temperatures, the steps 31 , 32 and 34 are repeated, until the main switch of the information board 10 is moved to the position "OPEN".
If it is found in step 31 that the temperature of the information board 10 has moved to the non-allowed temperature range, in this situation the operation branches to step 33. Then a part of the operations of the information board 10 are powered down by switching off voltage feed to the power supply 623 by an electronic switch arrangement 622. However, the fans of the information board preferably remain in operation. Their blow efficiency can be set to 10 - 100% of the maximum blow efficiency. Also in this situation, the control unit 62 measures the temperature inside the information board 10 if the operating switch of the information board is still in the "CLOSED" position. If the temperature returns to the allowed temperature range, the control unit 62 switches on the voltage feed to the power supply 623 again, whereby the power-up of the information board 10 starts according to the process described above.
Some preferred embodiments of the information board, control unit and control method of the information board according to the invention have been described above. The invention is not limited to the embodiments described above. For ex- ample, the TFT LCD display described in connection with the examples given in connection with the description can be replaced by some other display type, such as a plasma display. In addition, the inventive idea can be applied in numerous ways within the scope defined by the attached claims.

Claims

Claims
1. A control unit (62) of an electronic information board (10), characterized in that it comprises
- a direct voltage input (631)
- a power supply (623) comprising a plurality of voltage outputs (630, 640, 650, 660)
- an openable electronic connection between the direct voltage input (631) and the power supply (623)
- means (621) for measuring the temperature of the information board, and
- means (620, 622) for setting at least one voltage output (640, 650, 660) of the power supply in the "ON" or "OFF" state on the basis of the temperature measured from the information board (10).
2. A control unit according to Claim 1 , characterized in that the means for controlling the voltage outputs of the power supply (623) comprise
- a switching unit (620) and a temperature sensor (621) connected to it for measuring the temperature of the information board 10, and
- an electronic switch arrangement (622) connected to the switching unit (620), which is arranged to open or close the electrical connection (633) from the direct voltage input (631 ) to the power supply (623) on the basis of the temperature measurement.
3. A control unit according to Claim 2, characterized in that the switching unit (620) has been arranged to switch the direct voltage input (631) to the input of the power supply (623) only if the measured temperature in the information board (10) is in the temperature range allowed to it.
4. A control unit according to Claim 1 , characterized in that the voltage outputs (630, 640, 650, 660) of the power source (623) have different voltages.
5. A control unit according to Claim 4, characterized in that in the power supply (623) - the first voltage output (640) has been arranged to supply the operating voltage to the display unit (30)
- the second voltage output (650) has been arranged to supply the operating voltage to the backlight source, and
- the third voltage output (660) has been arranged to supply the operating voltage to the PC (61) controlling the information board (10).
6. A control unit according to Claim 4, characterized in that the fourth voltage output (630) of the power supply (623) has been arranged to supply operating voltage to the fans (72, 76), if the operating switch of the information board (10) is in the "CLOSED" position.
7. A control unit according to Claim 6, characterized in that the blow efficiency of the fans (72, 76) can be set to 15 - 100% of the maximum blow efficiency.
8. A control unit according to Claim 1 , characterized in that the display unit of the information board (10) is a TFT LCD display (30).
9. A control unit according to Claim 1 , characterized in that the display unit of the information board (10) is a plasma display.
10. A control unit according to Claim 1 , characterized in that the direct voltage input (631) has a voltage of +24 V.
11. An information board (10) comprising:
- a display unit (30)
- a voltage supply (63) of the information board, and
- means (72, 78, 80) for controlling the temperature of the information board (10),
characterized in that it also comprises a control unit (62), which comprises
- a direct voltage input (631 )
- a power supply (623) comprising a plurality of voltage outputs (630, 640, 650, 660)
- an openable electrical connection between the direct voltage input (631) and the power supply (623) - means (621) for measuring the temperature of the information board (10), and
- means (620, 622) for setting at least one voltage output (640, 650, 660) of the power supply (623) in the "ON" or OFF" state on the basis of the temperature measured from the information board (10).
12. An information board according to Claim 11 , characterized in that the display unit (30) is either a TFT LCD display or a plasma display.
13. An information board according to Claim 11 , characterized in that the voltage source (63) is a direct voltage source.
14. An information board according to Claim 11 , characterized in that the volt- age outputs (630, 640, 650, 660) of the power supply (623) have different voltages.
15. An information board according to Claim 14, characterized in that in the power supply (623)
- the first voltage output (640) has been arranged to supply the operating voltage to the display unit (30)
- the second voltage output (650) has been arranged to supply the operating voltage to the backlight source, and
- the third voltage output (660) has been arranged to supply the operating voltage to the PC (61) controlling the information board (10).
16. An information board according to Claim 15, characterized in that the fourth voltage output (630) of the power supply (623) has been arranged to supply operating voltage to the fans (72, 76), if the operating switch of the information board (10) is in the "CLOSED" position.
17. An information board according to Claim 16, characterized in that the blow efficiency of the fans (72, 76) can be set to 15 - 100% of the maximum blow efficiency.
18. A method for controlling the operation of the information board (10), in which method
- the power supply (30) of the information board is switched on - the PC controlling the information board is started for the power-up of the information board (35), and
- the information to be shown on the information board (10) is transferred from the PC to the display unit (36),
characterized in that additionally in the method
- the temperature of the information board (10) is measured continuously
- a comparison is made to determine whether the measured temperature is in the temperature range allowed for the information board (31)
- the supply of power to at least one of the components of the information board is switched off if the temperature of the information board is not in the allowed temperature range (33), and
- the supply of power is switched on again to said component of the information board, if the measured temperature is found to have returned to the allowed temperature range (31 , 32).
19. A method according to Claim 18, characterized in that the supply of power to the component of the information board (10) is switched off by switching off the supply of electricity between the direct voltage source (63) of the information board (10) and the power supply (623).
20. A method according to Claim 19, characterized in that the supply of power is switched off from other components of the information board (10) except the switching unit (620) and the fans (72, 76) of the information board (10).
PCT/FI2007/050090 2007-02-22 2007-02-22 Information board and its control unit WO2008102050A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/FI2007/050090 WO2008102050A1 (en) 2007-02-22 2007-02-22 Information board and its control unit

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US11191193B2 (en) 2008-12-18 2021-11-30 Manufacturing Resources International, Inc. System for cooling an electronic image assembly with circulating gas and ambient gas
US11540418B2 (en) 2008-03-03 2022-12-27 Manufacturing Resources International, Inc. Electronic display with cooling
US11617287B2 (en) 2019-02-26 2023-03-28 Manufacturing Resources International, Inc. Display assembly with loopback cooling
US11744054B2 (en) 2021-08-23 2023-08-29 Manufacturing Resources International, Inc. Fan unit for providing improved airflow within display assemblies
US11762231B2 (en) 2021-08-23 2023-09-19 Manufacturing Resources International, Inc. Display assemblies inducing turbulent flow
US11822171B2 (en) 2017-04-27 2023-11-21 Manufacturing Resources International, Inc. Field serviceable and replaceable assembly
US11889636B2 (en) 2018-07-30 2024-01-30 Manufacturing Resources International, Inc. Housing assembly for an integrated display unit
US11919393B2 (en) 2021-08-23 2024-03-05 Manufacturing Resources International, Inc. Display assemblies inducing relatively turbulent flow and integrating electric vehicle charging equipment

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US11540418B2 (en) 2008-03-03 2022-12-27 Manufacturing Resources International, Inc. Electronic display with cooling
US11596081B2 (en) 2008-03-03 2023-02-28 Manufacturing Resources International, Inc. Electronic display with cooling
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US11822171B2 (en) 2017-04-27 2023-11-21 Manufacturing Resources International, Inc. Field serviceable and replaceable assembly
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US11617287B2 (en) 2019-02-26 2023-03-28 Manufacturing Resources International, Inc. Display assembly with loopback cooling
US11744054B2 (en) 2021-08-23 2023-08-29 Manufacturing Resources International, Inc. Fan unit for providing improved airflow within display assemblies
US11762231B2 (en) 2021-08-23 2023-09-19 Manufacturing Resources International, Inc. Display assemblies inducing turbulent flow
US11919393B2 (en) 2021-08-23 2024-03-05 Manufacturing Resources International, Inc. Display assemblies inducing relatively turbulent flow and integrating electric vehicle charging equipment

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