JP2004132813A - Digital meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital mater capable of providing a subtle variation in hue only by using a drive pulse of different duty ratio, without tweaking a display device side. <P>SOLUTION: For a plurality of decorations 111a', 113a', and 115a' formed of a light emitting element of an equivalent color assigned to a prescribed display point of a display device 11', drive pulses of a different duty ratio are generated and applied as the drive signal for the display device 11'. Thus, a plurality of decorations formed with a light emitting element of the equivalent color are provided with the subtle variation in hue, only by using the drive pulses of the different duty ratio. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a digital meter, and more particularly, to a digital meter that uses a fluorescent display tube as a display device and is used for a vehicle-mounted combination meter or the like.
[0002]
[Prior art]
2. Description of the Related Art In recent years, a so-called digital meter, in which information such as vehicle speed, engine speed, fuel, and A / T position is arithmetically processed by a microcomputer and digitally displayed by a VFD (fluorescent display tube), a light emitting diode, a liquid crystal, or the like, has become widespread. I have. Conventionally, in this type of digital meter, a static, that is, a drive pulse having a duty ratio of 100% is uniformly used for each design assigned to a vehicle speed, an engine rotation speed, a fuel, and the like. It emits light.
[0003]
By the way, there are many designs related to the vehicle speed, the engine rotation speed, the fuel, the A / T position, etc., and the same color is often assigned irrespective of different display targets. For example, the red zone design related to the display of the engine speed, the position R design related to the display of the A / T position, the remaining lamp design related to the display of the fuel (both refer to FIG. 2), etc. Often displayed.
[0004]
[Problems to be solved by the invention]
Basically, when the display targets are different, it is preferable to assign different colors to differentiate them more accurately. However, in the conventional digital meter, the above-described designs are made to emit light by uniformly using a static drive pulse. Therefore, when the phosphor contained in the display device has the same color, it naturally emits the same color. Will be. Therefore, in order to give each design a subtle color difference, use of a cadmium pigment or the like is assumed. This complicates the manufacturing process of the meter, and is not environmentally desirable.
[0005]
Accordingly, the present invention has been made in view of the above-described situation, and has been made to provide a digital meter having a slight color difference by using drive pulses of different duty ratios without changing the display device side. It is an issue.
[0006]
[Means for Solving the Problems]
A digital meter according to claim 1, which has been made to solve the above-mentioned problem, has a display device capable of individually displaying a plurality of types of information in response to a predetermined drive signal as shown in a basic configuration diagram of FIG. 11 ′, a plurality of designs 111 a ′, 113 a ′ 115 a ′ formed of light-emitting elements of the same color assigned as the plurality of types of information at predetermined display locations of the display device 11 ′, and the plurality of designs And display control means 12 'for generating drive pulses having different duty ratios respectively corresponding to the above, and applying the drive pulses to the display device 11' as the drive signals.
[0007]
According to the first aspect of the present invention, drive pulses having different duty ratios are generated for a plurality of designs formed of light emitting elements of the same color allocated to a predetermined display location of the display device 11 ', and this is generated. It is applied as a drive signal for the display device 11 '. Therefore, only by using the drive pulses having different duty ratios, it is possible to give a subtle color difference to a plurality of designs formed by light emitting elements of the same color.
[0008]
In order to solve the above-mentioned problems, a digital meter according to claim 2 is, as shown in the basic configuration diagram of FIG. 1, in the digital meter according to claim 1, wherein the display control means 12 ' Among them, for a design having a high lighting probability, a drive pulse having a lower duty ratio is generated than for a design having a low lighting probability, and applied to the display device 11 'as the drive signal. It is characterized by.
[0009]
According to the second aspect of the present invention, a drive pulse having a lower duty ratio is generated for a design having a high lighting probability and applied to the display device 11 'than a design having a low lighting probability. As a result, power consumption can be reduced.
[0010]
According to a third aspect of the present invention, there is provided a digital meter according to the second aspect, wherein the design comprises a first design having a high lighting probability. ′, A third design 111a ′ having a lower lighting probability, and a second design 115a ′ having an intermediate lighting probability between the first design 113a ′ and the third design 111a ′. A first drive pulse having a duty ratio, a third drive pulse having a lower duty ratio, and a second drive pulse having a duty ratio intermediate between the first drive pulse and the third drive pulse; 113a ', the second design pulse 115a', and the third design 111a ', respectively, corresponding to the third drive pulse, the second drive pulse, and the first drive pulse. , It applied, characterized in that.
[0011]
According to the third aspect of the present invention, since drive pulses having different duty ratios are applied stepwise in accordance with predetermined designs having different lighting probabilities, generation and display control of each drive pulse are performed. There is no complication.
[0012]
A digital meter according to a fourth aspect of the present invention has been made in order to solve the above problem. As shown in the basic configuration diagram of FIG. 1, the digital meter according to any one of the first to third aspects, ′ Is a fluorescent display tube provided with a plurality of display segments respectively corresponding to the plurality of designs.
[0013]
According to the fourth aspect of the present invention, it is only necessary to apply a drive pulse having the above-described duty ratio to the corresponding terminal of the fluorescent display tube in order to give a plurality of designs a slight difference in color.
[0014]
A digital meter according to a fifth aspect of the present invention has been made to solve the above-mentioned problem. As shown in the basic configuration diagram of FIG. 1, the digital meter according to any one of the first to fourth aspects, Is a vehicle-mounted combination meter that emits light in a red system.
[0015]
According to the fifth aspect of the present invention, the plurality of designs emit light in a red system and are more effective when applied to a vehicle-mounted combination meter. In other words, red color systems, including red zones and various alarms, are frequently used in vehicle-mounted combination meters. In this way, a subtle color difference is provided, and each meter section can be more clearly differentiated.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 2 is a front view showing a VFD used as a display device according to an embodiment of the digital meter of the present invention. VFD is a well-known device, and is a kind of vacuum tube that utilizes the phenomenon of excitation and emission of a light emitter by an electron beam. When a voltage is applied to the filament as the cathode, the filament is overheated and emits thermoelectrons. A positive voltage is applied to the grid, usually using a metal mesh. Then, uniform diffusion is performed by controlling the acceleration of electrons from the filament to the display segment as the anode. The display segment is coated with a luminous body corresponding to each design, and is accelerated by applying a positive voltage to the display segment, causing a light emission phenomenon due to electrons that collide with the phosphor surface.
[0017]
As shown in FIG. 2, the VFD 11 is used as a display device of a digital meter such as a vehicle-mounted combination meter, and includes a full gauge unit 111, an odometer / trip meter unit 112, a tachometer unit 113, a speedometer unit 114, and an A / T. A position display section 115 is assigned. Here, the VFD 11 is mounted on a circuit board (not shown). On the back side of the VFD 11, a VFD drive circuit, a microcomputer, an interface circuit, and the like, which are also mounted on a circuit board, are arranged. This type of digital meter also has various warning units, direction indicating units, and the like, which are assumed to be assigned to other than the VFD 11. These assignments can be changed as appropriate.
[0018]
By using the VFD 11 as the display device, it is possible to easily give a subtle color difference to a desired design while promoting simplification of the meter. That is, it is possible to express a delicate color difference only by applying drive pulses having respective duty ratios to be described later to the terminals of the VFD 11 corresponding to the desired design.
[0019]
Fuel gauge section 111 includes a bar graph design displaying a level corresponding to the current remaining fuel amount. The fuel gauge section 111 includes a character design indicating a fuel full F and a fuel empty E, and a design indicating a scale or the like. In particular, the fuel gauge unit 111 includes a remaining amount lamp design 111a that emits light when the remaining amount of fuel falls below a predetermined alarm level.
[0020]
The odometer / trip meter unit 112 includes a numerical design indicating a value corresponding to a change in the light emitting element according to the current accumulated traveling distance corresponding to each of the odometer unit and the trip meter unit (consisting of the A mode and the B mode), and It includes a character design indicating the A mode or the B mode of the trip meter section.
[0021]
The tachometer section 113 includes numerical designs (0, 1,..., 8) and scales corresponding to typical engine rotation speeds, and bar graph-like designs of colors corresponding to each engine rotation speed. The bar graph-like design is, for example, a red-based red zone design 113a along the 7-8 numerical design indicating the engine rotation speed, and a blue-based design along the other numerical design indicating the rotation speed. Become. The design including the red zone design 113a emits light of a predetermined color as long as the ignition is ON regardless of the engine rotation speed. In addition, the tachometer section 113 includes a bar graph design in which a light emitting element changes according to the engine rotation speed and indicates the engine rotation speed.
[0022]
The speedometer section 114 includes a numeric design in which the light emitting element changes according to the vehicle speed and indicates a corresponding value. Also, the A / T position display section 115 includes a symbol design including characters corresponding to the position P (parking), the position R (reverse), the position N (neutral), and the position D (drive). Each of these designs emits light in accordance with a drive pulse having a predetermined duty ratio.
[0023]
Note that the display unit including such a VFD 11 is held and housed in a not-shown facing, main body cover, back cover, or the like as a part of the meter housing. In addition, a well-known dark black surface glass is covered on the front surface of the display unit. A digital meter including such a display unit is attached to an instrument panel at a front portion of a vehicle.
[0024]
Next, the electrical configuration and operation of the digital meter according to one embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a block diagram showing a configuration according to an embodiment of the digital meter of the present invention. FIGS. 4A to 4C are time charts illustrating drive pulses according to the digital meter of one embodiment of the present invention.
[0025]
As shown in FIG. 3, the digital meter 1 includes the VFD 11 and the electronic circuit unit 12. Further, a level sensor 13, a rotation sensor 14, a vehicle speed sensor 15, and the like are connected to the electronic circuit section 12 of the digital meter 1.
[0026]
The VFD 11 is as described above. However, in addition, the fuel gauge unit 111 included in the VFD 11 emits a corresponding predetermined design based on a sensor signal from the level sensor 13. The odometer / trip meter unit 112 emits a light corresponding to a predetermined design based on a sensor signal from the vehicle speed sensor 15. The tachometer section 113 and the speedometer section 114 emit a corresponding predetermined design based on sensor signals from the rotation sensor 14 and the vehicle speed sensor 15, respectively. The A / T position display section 115 causes a corresponding predetermined design to emit light based on the A / T position signal.
[0027]
The same red phosphor is used for the remaining lamp design 111a included in the full gauge unit 111, the red zone design 113a included in the tachometer unit 113, and the position R design 115a included in the A / T position display unit 115. However, it is possible to express a subtle difference in hue by driving pulses having different duty ratios. This will be described again later. The remaining lamp design 111a, the red zone design 113a, and the position R design 115a correspond to the third design, the first design, and the second design, respectively.
[0028]
The electronic circuit unit 12 includes a VFD drive circuit 121, a microcomputer 122, and an interface circuit 123. The VFD drive circuit 121 includes, for example, an inverter circuit, and responds to a dimming signal from the microcomputer 122 to drive pulses having different duty ratios as shown in FIGS. Is generated and applied to the VFD 11. The electronic circuit unit 12 corresponds to a display control unit in the claims.
[0029]
As shown in FIGS. 4 (A), 4 (B) and 4 (C), in the present embodiment, drive pulses having a duty ratio of 50%, 75% and 100% are used to drive the VFD 11. . The drive pulses having these duties are composed of a high-level signal (H) and a low-level signal (L) that constitute one cycle (corresponding to a period indicated by 100%) so as to correspond to each duty ratio.
[0030]
The microcomputer 122 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Anytime Write / Read Memory), not shown. The CPU executes various processes including the control according to the present embodiment according to a control program stored in the ROM. In particular, the CPU determines the duty ratio of the drive pulse according to each sensor signal, each A / T position signal, and the like by referring to a table stored in the ROM. Then, a PWM signal corresponding to the duty ratio is applied to the VFD drive circuit 121 as the dimming signal.
[0031]
The interface circuit 123 converts the level sensor 13, the rotation sensor 14, the vehicle speed sensor 15, the A / T position signal, the IGN signal, and the like into digital signals of a level that can be processed by the microcomputer 122, Output.
[0032]
The level sensor 13 is mounted in the fuel tank and outputs a sensor signal according to the remaining fuel level. The rotation sensor 14 and the vehicle speed sensor 15 detect the rotation speed and the vehicle speed of the engine, respectively, and output sensor signals corresponding to these. The A / T position signal is a signal indicating each position of the A / T lever, that is, position P (parking), position R (reverse), position N (neutral), position D (drive), and the like. The IGN (ignition) signal is a signal emitted when the engine key is set to, for example, the position ON. Since the sensor signal, the A / T position signal, and the IGN signal are well known, a detailed description thereof will be omitted.
[0033]
Next, the operation of the digital meter having such a configuration will be described. However, description of various warning units and direction indicating units that are not directly related to the present embodiment will be omitted here.
[0034]
When the microcomputer 122 detects the above-mentioned IGN signal and further detects each sensor signal and A / T position signal, the VFD drive circuit 121 passes through the full gauge section 111, the odometer / trip meter section 112, the tachometer A predetermined drive pulse is applied to each segment corresponding to each design in the section 113, the speedometer section 114, and the A / T position display section 115, and the corresponding design emits light.
[0035]
Before traveling, the engine rotation including a bar graph design indicating the current fuel remaining amount in the fuel gauge unit 111, a numerical design indicating the current accumulated traveling distance in the odometer / trip meter unit 112, and a red zone design 113a in the tachometer unit 113. Numerical design indicating speed, bar graph design 113b according to scale and engine speed at idling, numerical design indicating vehicle speed "0" in speedometer unit 114, position P (parking) in A / T position display unit 115 And the character design corresponding to position N (neutral) emits light. In particular, at this stage, the red zone design 113a in the tachometer unit 113 emits red light in response to the drive pulse having the duty ratio of 50% shown in FIG.
[0036]
Next, during traveling, the fuel gauge unit 111 includes a bar graph design indicating the current fuel remaining amount, the odometer / trip meter unit 112 includes a numeric design indicating the current accumulated traveling distance, and the tachometer unit 113 includes a red zone design 113a. Numerical design indicating engine rotational speed, bar graph design 113b according to scale and engine rotational speed during traveling, numerical design indicating vehicle speed in speedometer section 114, and A / T position in A / T position display section 115 The character design that emits light. In particular, at this stage, at the start of traveling or at the time of traveling stop, the A / T position is often set to the position R, and in response to this, in response to a driving pulse having a duty ratio of 75% shown in FIG. The position R design 115a emits light in amber. Here, the red zone design 113a emits red light.
[0037]
Further, when the vehicle continues to travel and the remaining fuel level falls below a predetermined alarm level, the remaining power lamp design 111a emits a bright orange light in response to a driving pulse having a duty ratio of 100% shown in FIG. I do. Note that, also here, the red zone design 113a emits red light. Also, here, when the A / T position is set to the position R115a, the position R design 115a emits light in amber in response to a drive pulse having a duty ratio of 75% shown in FIG. 4B.
[0038]
In this way, by simply changing the duty ratio of the drive pulse as described above, the red zone design 113a made of the same red phosphor is made to emit red light, the position R design 115a is made to emit light in amber, and The quantity lamp design 111a can emit light in bright orange. In addition, a drive pulse having a lower duty ratio is applied to a design having a high lighting probability, for example, to the red zone design 113a, than to a design having a low lighting probability, for example, to the remaining lamp design 111a. Therefore, it can contribute to lower power consumption.
[0039]
The present invention is not limited to the above embodiment, and can be appropriately changed without departing from the gist of the present invention. For example, the duty ratio of the drive pulse is not limited to the above embodiment, and may be another duty ratio. In addition, the drive pulse can be applied to, for example, a blue or yellow design other than a design that emits light in a red system. Further, the present digital meter can be applied to other than a vehicle-mounted combination meter.
[0040]
【The invention's effect】
As described above, according to the first aspect of the present invention, drive pulses having different duty ratios are applied to a plurality of designs formed of light emitting elements of the same color assigned to a predetermined display location of a display device. Generated and applied as a drive signal for the display device. Therefore, by using only drive pulses with different duty ratios without changing the display device side, a subtle color difference can be provided for a plurality of designs formed by light emitting elements of the same color. Become like
[0041]
According to the second aspect of the present invention, a drive pulse having a lower duty ratio is generated for a design with a high lighting probability and applied to a display device than a design pulse with a low lighting probability. Therefore, it is possible to contribute to lower power consumption while enjoying the above effects.
[0042]
According to the third aspect of the present invention, since drive pulses having different duty ratios are applied stepwise in accordance with predetermined designs having different lighting probabilities, generation and display control of each drive pulse are performed. Thus, a digital meter that is realistic and can be obtained without being complicated.
[0043]
According to the fourth aspect of the present invention, since the fluorescent display tube is used as the display device, the above effects can be obtained while simplifying the entire meter. That is, it is only necessary to apply a drive pulse having the above-described duty ratio to the corresponding terminal of the fluorescent display tube in order to give a plurality of designs a slight difference in color as described above.
[0044]
According to the fifth aspect of the present invention, the plurality of designs emit red light and are applied to an in-vehicle combination meter, so that the above effect can be more remarkably obtained. That is, a red system including a red zone and various alarms is frequently used in an on-board combination meter, and the above-described red system design included in each of the meter units constituting such a combination meter is described above. In this way, a subtle color difference is provided, and each meter section can be more clearly differentiated.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration of a digital meter according to the present invention.
FIG. 2 is a front view showing a VFD used as a display device according to an embodiment of the digital meter of the present invention.
FIG. 3 is a block diagram showing a configuration according to an embodiment of the digital meter of the present invention.
FIGS. 4A to 4C are time charts illustrating a drive pulse according to the digital meter of one embodiment of the present invention.
[Explanation of symbols]
1 Digital meter 11 VFD
12 Electronic circuit unit 13 Level sensor 14 Rotation sensor 15 Vehicle speed sensor 111 Fuel gauge unit 112 Od / trip meter unit 113 Tachometer unit 114 Speed meter unit 115 A / T position display unit 111a Remaining lamp design 113a Red zone design 115a Position R design 121 VFD drive circuit 122 Microcomputer 123 Interface circuit

Claims (5)

A display device capable of individually displaying a plurality of types of information in response to a predetermined drive signal;
A plurality of designs formed of light emitting elements of the same color assigned as the plurality of types of information, at a predetermined display location of the display device,
Display control means for generating drive pulses having different duty ratios respectively corresponding to the plurality of designs, and applying the drive pulses to the display device as the drive signal;
A digital meter comprising: The digital meter according to claim 1,
The display control means, among the plurality of designs, for a design with a high lighting probability, than for a design with a low lighting probability, generates a drive pulse with a lower duty ratio, and as the drive signal Applied to the display device,
A digital meter, characterized in that: The digital meter according to claim 2,
The design includes a first design having a high lighting probability, a third design having a lower lighting probability, and a second design having an intermediate lighting probability between the first design and the third design.
The driving pulse includes a first driving pulse having a high duty ratio, a third driving pulse having a lower duty ratio, and a second driving pulse having a duty ratio intermediate between the first driving pulse and the third driving pulse. Including
The third drive pulse, the second drive pulse, and the first drive pulse are applied corresponding to the first design, the second design, and the third design, respectively.
A digital meter, characterized in that: The digital meter according to any one of claims 1 to 3,
The display device is a fluorescent display tube including a plurality of display segments respectively corresponding to the plurality of designs,
A digital meter, characterized in that: The digital meter according to any one of claims 1 to 4,
The plurality of designs emits light in a red system, and is a vehicle-mounted combination meter.
A digital meter, characterized in that:

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