JP2004271258A - Instrument for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an instrument for automobiles for securing visibility in beam attenuation. <P>SOLUTION: A main light source 18 for irradiating a dial 14 with light from the rear side is provided, and an auxiliary light source 20 is provided. Then, when the degree of dimming in a dimmer is smaller than a specific value, only the main light source is driven so that the luminance of emission in the main light source decreases with a specific decrease rate according to the degree of dimming in the dimmer. When the degree of dimming in the dimmer is equal to or more than a specific value, the main light source 18 and the auxiliary light source 20 are driven according to the degree of dimming in the dimmer so that the emission luminance of the total of the main light source 18 and the auxiliary light source 20 becomes larger than a case, where the emission luminance of the main light source 18 decreases with a specific decrease rate. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an instrument for a vehicle, and more particularly to an instrument for a vehicle such as a combination meter provided in an automobile.
[0002]
[Prior art]
Generally, an automobile is provided with a combination meter including a plurality of instruments such as a speedometer, a tachometer, a fuel gauge, and a water temperature gauge, and the state of the automobile can be grasped by the combination meter. I have.
[0003]
Such a combination meter is provided with a light source on the back surface, and is configured to be easily visible even when the surroundings are dark, such as at night, through the dial. As the light source, for example, a light source such as an incandescent lamp or a light emitting diode is used.
[0004]
Some light sources are provided with a dimmer, and the dimmer generally controls a driving voltage or current for driving the light source to adjust luminance.
[0005]
On the other hand, a plurality of meters provided in the combination meter have portions for displaying in a plurality of colors such as red and white. The light amount of the part displayed in red is cut by the printed layer of the part displayed in red compared to the part originally displayed in white, so that the light transmission is small. Is not a problem, but at the time of dimming, the difference in the amount of transmitted light becomes visible. Therefore, in the technology described in Patent Document 1, by using a fluorescent lamp that emits light rays having light emission characteristics close to the display color of the display pattern as a lighting member, the color of the display pattern by the lighting member is made thinner than the originally intended color and the visibility is improved. In addition, the display pattern in which illumination by the fluorescent lamp is not desirable is provided with a complementary color member to suppress the influence of the fluorescent lamp.
[0006]
[Patent Document 1]
JP-A-6-050775 (page 1, FIG. 1)
[0007]
[Problems to be solved by the invention]
In a vehicle instrument provided with a conventional light control device, brightness is changed by variably controlling a drive voltage and a current of a light source, and does not have a function of changing chromaticity and lightness. When a light-emitting diode or the like is used as a light source of this type, luminance changes due to dimming due to its light-emitting principle, but chromaticity does not change, and desired brightness can be obtained. However, when the dimming ratio is about 1/10 or less (about 10 cd / m ² or less in luminance), the darkness becomes darker, that is, the display brightness is reduced and the visibility is reduced due to human visual perception. There is a problem that it decreases.
[0008]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and has as its object to provide an automotive instrument capable of securing visibility at the time of dimming.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 provides a light source that irradiates a display pattern of an instrument, a dimming unit that dims light of the light source, and a dimming degree by the dimming unit. Correction means for correcting the characteristics of the light applied to the display pattern.
[0010]
According to the first aspect of the invention, the display pattern of the instrument (for example, a display pattern representing a speedometer, a tachometer, a water temperature gauge, a fuel gauge, and the like) is irradiated with light by the light source. In the dimming means, the light of the light source is dimmed. That is, the emission luminance is increased or decreased.
[0011]
By the way, when the light of the light source is dimmed by the dimming means, the display pattern looks dark in human visual sense as described above. Therefore, the characteristics (for example, chromaticity, lightness, etc.) of the light applied to the display pattern are corrected by the correction unit according to the dimming degree of the dimming unit. In other words, when the light source is dimmed, it is possible to correct, by the correction means, that the display putter looks blackish due to human visual perception. Therefore, visibility at the time of dimming can be ensured.
[0012]
Here, the correcting means corrects the brightness of the light source according to the dimming degree by the adjusting means as in the invention according to claim 2, and displays when the light source is dimmed by the dimming means. Since the brightness of the light applied to the pattern can be increased, it is possible to prevent the display pattern from appearing dark.
[0013]
Further, as the correcting means, an auxiliary light source for irradiating light having a desired brightness with light modulated according to the dimming degree of the dimming means is used. Can be. For example, when increasing the brightness of light applied to a display pattern, an auxiliary light source that emits light having the same color as the color of the light source and higher in brightness than the light of the light source or an auxiliary light source that emits light such as white light is used. Thereby, the brightness of the light applied to the display pattern can be corrected.
[0014]
Further, when the light of the light source is dimmed by the dimming means, the display pattern looks dark on human visual perception as described above. When the dimming degree is higher than a predetermined value, by driving the auxiliary light source, the brightness of the light applied to the display pattern is corrected, and the display pattern can be prevented from appearing black.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
[0016]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of a vehicle instrument 10 according to an embodiment of the present invention.
[0017]
As shown in FIG. 1, a vehicle instrument 10 according to an embodiment of the present invention is provided with a transparent instrument protection plate 12 on the driver's viewpoint A side, and inside the instrument protection plate 12. The dial 14 is provided with a predetermined display pattern (for example, a display pattern indicating a speedometer, a tachometer, a fuel gauge, a water temperature gauge, an oil pressure gauge, and the like). The display pattern of the dial 14 is formed of a light transmissive member, and transmits light of a light source described later.
[0018]
Inside the dial 14, an instrument board 16 is provided. On the instrument board 16, a main light source 18 irradiating the dial 14 from the back side is provided, and an auxiliary light source 20 is provided. I have. In FIG. 1, one light source 18 and one auxiliary light source 20 are shown, but a plurality of light sources 18 and auxiliary light sources 20 may be arranged. Further, the main light source 18 and the auxiliary light source 20 may be configured to be sealed in the same structure. That is, a plurality of main light sources 18 and auxiliary light sources 20 may be arranged on a single substrate.
[0019]
In the present embodiment, the main light source 18 and the auxiliary light source 20 use light emitting diodes. Then, an auxiliary light source 20 that obtains desired luminance and brightness is selected according to the light emission characteristics of the main light source 18. For example, the auxiliary light source 20 selects a light source having a chromaticity such as a white color whose lightness increases when mixing colors or a light source having the same color as the main light source 18 and a high lightness.
[0020]
Further, the automotive instrument 10 according to the embodiment of the present invention includes a reflector 22 for diffusing light emitted from the main light source 18 and the auxiliary light source 20, and is irradiated with the light from the main light source 18 and the auxiliary light source 20. Light is applied to the entire dial 14 by the reflector 22. The reflector 22 may not be set according to the number and arrangement of the main light source 18 and the auxiliary light source 20.
[0021]
Subsequently, a configuration of a control system of the automotive instrument 10 according to the embodiment of the present invention will be described with reference to FIG.
[0022]
As shown in FIG. 2, the automotive instrument 10 includes an illumination control unit 24 that controls lighting of the main light source 18 and the auxiliary light source 20. The illumination control unit 24 can be configured by a microcomputer including a CPU, a ROM, a RAM, and the like, for example.
[0023]
The illumination control unit 24 includes a lighting switch 26 for turning on the illumination (the main light source 18 and the auxiliary light source 20) of the vehicle instrument 10 and a dimmer (for example, increasing or decreasing the brightness) of the illumination of the automobile instrument 10. An optical device 28 is connected, and lighting of the main light source 18 and the auxiliary light source 20 is controlled in accordance with ON / OFF of the illumination switch 26 and dimming of the dimming device 28. The lighting switch 26 can also be used as a switch for turning on a lighting device such as a headlight, for example.
[0024]
A driver 30 for driving the main light source 18 and the auxiliary light source 20 is connected to the illumination control unit 24, and the main light source 18 and the auxiliary light source 20 are driven by the driver 30. For example, the driver 30 drives the main light source 18 and the auxiliary light source 20 by pulse driving the main light source 18 and the auxiliary light source 20 and controlling the duty ratio of the driving current and voltage.
[0025]
Specifically, the illumination control unit 24 drives the main light source 18 and the auxiliary light source 20 to have the light emission luminance shown in FIG. 3 according to the dimming degree of the dimmer 28. That is, until the light control degree of the light control device 28 reaches a predetermined value D1 (the light emission luminance of the main light source 18 is the light emission luminance L1), the main light source 18 decreases such that the light emission luminance decreases at a predetermined reduction rate in accordance with the light control degree. Only drive. When the dimming degree of the dimmer 28 is equal to or greater than the predetermined value D1, as shown by the dotted line in FIG. 3, the main light source 18 is controlled so that the light emission luminance of the main light source 18 becomes larger than the predetermined reduction rate. And is driven such that the light emission luminance of the auxiliary light source 20 increases at a predetermined increase rate, as shown by the dashed line in FIG. That is, as shown by the two-dot line in FIG. 3, the total light emission luminance of the main light source 18 and the auxiliary light source 20 is slightly larger than the case where the light emission luminance of the main light source 18 decreases at a predetermined reduction rate. To be driven. Note that the drive values of the main light source 18 and the auxiliary light source 20 that have a light emission luminance corresponding to the dimming degree of the dimming device 28 shown in FIG.
[0026]
Next, the illumination drive control performed by the illumination control unit 24 of the automotive instrument 10 configured as described above will be described with reference to the flowchart of FIG.
[0027]
First, in step 100, it is determined whether or not the lighting switch 26 has been turned on. If the determination is negative, the process waits until the result is affirmative and proceeds to step 102.
[0028]
In step 102, the dimming degree of the dimmer 28 is detected, and the process proceeds to step 104.
[0029]
In step 104, it is determined whether or not the dimming degree of the dimmer 28 detected in step 102 is equal to or greater than a predetermined value D1. If the determination is negative, the process proceeds to step 106, Only the main light source 18 is driven according to the dimming degree. That is, as shown in FIG. 3, when the dimming degree of the dimmer 28 is smaller than the predetermined value D1, the light emission luminance of the main light source 18 is reduced by a predetermined rate according to the dimming degree of the dimmer 28. , Only the main light source 18 is driven.
[0030]
On the other hand, if the determination in step 104 is affirmative, the process proceeds to step 108, where the main light source 18 and the auxiliary light source 20 are driven according to the dimming degree of the dimmer. That is, as shown in FIG. 3, when the dimming degree of the dimmer 28 is equal to or more than the predetermined value D1, as shown by the two-dot line in FIG. The main light source 18 and the auxiliary light source 20 are driven according to the dimming degree of the dimming device 28 so that the total light emission luminance of the main light source 18 and the auxiliary light source 20 becomes larger than the case where the luminance is reduced. By driving the main light source 18 and the auxiliary light source 20 in this way, it can be seen that the brightness appears to be low due to human visual perception when the illumination (main light source 18) is dimmed, as shown by the dotted line in FIG. Can be corrected. That is, the brightness of the illumination of the automotive instrument 10 can be corrected in accordance with the dimming state of the illumination of the automotive instrument 10, and from the viewpoint of human sensation, the display pattern is suppressed from appearing darker as the illumination decreases. Therefore, visibility at the time of dimming can be ensured.
[0031]
Here, another configuration example of the control system of the automotive instrument 10 according to the embodiment of the present invention will be described. The main light source 18 and the auxiliary light source 20 will be described in the case where a light emitting diode is applied as in the above embodiment, and the same components as those in the above embodiment will be described with the same reference numerals.
[0032]
As shown in FIG. 6, the automotive instrument includes an illumination control circuit 50 that controls lighting of the main light source 18 and the auxiliary light source 20.
[0033]
The respective terminals on the cathode side of the main light source 18 and the auxiliary light source 20 are connected to the illumination control circuit 50, and the respective terminals on the anode side are connected to one end of the illumination switch 26 of the automotive instrument. The other end of the illumination switch 26 is connected to a positive terminal of the battery 52. The negative terminal of the battery 52 is grounded.
[0034]
The lighting control circuit 50 is grounded, and is connected to a dimming device 52 for dimming the lighting of the automotive instrument.
[0035]
That is, when the illumination switch 26 is in the ON state, the brightness of the main light source 18 and the auxiliary light source 20 is adjusted by the dimmer 52. For example, the illumination control circuit 50 and the dimming device 52 are configured to include variable resistors, and adjust the brightness of each by changing the drive current and the like of the main light source 18 and the auxiliary light source 20.
[0036]
Specifically, as shown in FIG. 3 described above, the illumination control circuit 50 drives the main light source 18 such that the luminance of the main light source 18 decreases at a predetermined reduction rate until the dimming degree by the dimmer 52 reaches a predetermined value D1. I do. When the dimming degree of the dimming device 52 is equal to or more than the predetermined value D1, the main light source 18 and the auxiliary light source 20 are driven, and the total luminance of the main light source 18 and the auxiliary light source 20 is reduced to the main light source. The luminance of No. 18 is set to be larger than when the luminance decreases at a predetermined reduction rate.
[0037]
In the above-described embodiment, the main light source 18 and the auxiliary light source 20 are pulse-driven to control and drive the duty ratios of the main light source 18 and the auxiliary light source 20 according to the dimming of the dimmer 28. However, the driving current or the driving voltage may be simply varied by the variable resistor and controlled as described above, and the same effect as in the above embodiment can be obtained by such a configuration.
[0038]
In the above embodiment, the configuration in which the main light source 18 and the auxiliary light source 20 are provided on the back surface of the dial 14 is not limited to this. For example, as shown in FIG. An auxiliary light source 20 may be provided between the dials 14, and the main light source 18 may be provided on the back side of the dial 14. That is, in this case, when the brightness correction is not performed, light is irradiated from the back side of the dial 14 by the main light source 18, and when the brightness is corrected at the time of dimming, the main light source 18 is irradiated from the back side of the dial 14. At the same time as the light is emitted, the light is emitted from the front side of the dial 14 by the auxiliary light source 20.
[0039]
Further, the present invention can be applied to a case where a liquid crystal display (LCD) or the like is used as a dial of a vehicle instrument. For example, as shown in FIG. 8, an LCD 60 that displays a predetermined display pattern (for example, a display pattern indicating a speedometer, a tachometer, or the like) is provided inside the instrument protection plate 12. The main light source 18 and the auxiliary light source 20 described above are provided on the rear surface side of the LCD 60, and a diffusion plate 62 for diffusing radiation emitted from the main light source 18 and the auxiliary light source 20 is provided on the LCD 60, the main light source 18, and the auxiliary light source. 20. In the automotive meter configured as described above, the same effect as described above can be obtained by turning on the main light source 18 and the auxiliary light source 20 according to the dimming state of the dimmer as in the above-described embodiment. Can be.
[0040]
Further, in the above embodiment, the main light source 18 and the auxiliary light source 20 employ light emitting diodes. However, the present invention is not limited to this. For example, electroluminescence (a so-called EL element), an incandescent bulb, or the like is applied. It is also possible.
[0041]
【The invention's effect】
As described above, according to the present invention, it is possible to correct the characteristics of the light radiated on the display pattern by providing the correction means for correcting the characteristics of the light radiated on the display pattern of the meter. Can be prevented from appearing dark, so that visibility at the time of dimming can be ensured.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a schematic configuration of an automotive instrument according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a control system of the automotive instrument according to the embodiment of the present invention.
FIG. 3 is a graph showing light emission luminance characteristics of a main light source and an auxiliary light source that emit light in accordance with a dimming degree.
FIG. 4 is a flowchart illustrating an example of lighting control performed by a lighting control unit of the automotive instrument according to the embodiment of the present invention.
FIG. 5 is a graph showing a result of performing brightness correction using an auxiliary light source in addition to a main light source.
FIG. 6 is a diagram showing another configuration of the control system of the automotive instrument.
FIG. 7 is a diagram showing a configuration example in a case where an auxiliary light source is provided on a front surface side of a dial in a vehicle instrument according to an embodiment of the present invention.
FIG. 8 is a diagram showing an example of a configuration in a case where a liquid crystal display device is used as a dial in the automotive instrument according to the embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 10 Automotive instrument 14 Dial 18 Main light source 20 Auxiliary light source 24 Lighting control unit 28 Light control device 30 Driver 50 Lighting control circuit 52 Light control device

Claims (4)

A light source for illuminating the display pattern of the instrument,
Dimming means for dimming the light of the light source,
Correction means for correcting the characteristics of light emitted to the display pattern according to the dimming degree by the dimming means,
Automotive instrument with a. The automotive instrument according to claim 1, wherein the correction unit corrects the brightness of the light source according to a dimming degree of the dimming unit. 3. The automotive instrument according to claim 2, wherein said correction means comprises an auxiliary light source for irradiating the light adjusted by said light adjustment means with light having a desired brightness. The automotive instrument according to claim 3, wherein the auxiliary light source is driven when a dimming degree by the dimming unit is equal to or more than a predetermined value.

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