JP2011113022A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device capable of improving accuracy of recognizing day and night, without depending on wavelength dependency of a light sensor. <P>SOLUTION: The display device includes: a display part; a spectrum acquiring part which creates distribution information for indicating distribution of optical energy for each wavelength, by performing photo-electric conversion by separating incident light for each wavelength; a ratio calculation part for calculating a ratio of the optical energy of a plurality of predetermined wavelengths, based on the distribution information; a light source determination part for determining a classification of a light source of the incident light based on the calculated ratio; and a display control part for controlling a light emission amount of the display part, based on the determination result and a light-receiving amount received by the spectrum acquiring part. The display control part controls so that the light emission amount of the display part is increased when the determination result indicates natural light, and that the light emission amount of the display part is decreased when the determination result indicates artificial light. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a display device that is used by being transported by a moving body such as a human being or a vehicle, and more particularly to a display device having a function of adjusting a light emission amount according to a light amount around the device.

  Display devices that are assumed to be transported and used by a moving body, such as portable navigations and mobile phones, that control the light emission amount of the display unit according to the brightness around the device have been put into practical use. .

  For example, a display device that determines day and night by putting incident light on the display device with a light sensor and determining the threshold value of the magnitude of a signal output from the light sensor has been put into practical use. Based on the determination result, the backlight included in the display unit is adjusted to a necessary and sufficient amount of light, thereby saving power and improving visibility.

  However, since the characteristics of different materials constituting the optical sensor are different, it is necessary to use different optical sensors suitable for the wavelength distribution characteristics of ambient light. FIG. 10 shows the light receiving sensitivity for each wavelength of the optical sensors whose materials are silicon (= Si), gallium (= Ga), and indium gallium arsenide (= InGaAs), respectively.

  For example, silicon is suitable for receiving light having a wavelength of 300 nm to 1100 nm, whereas gallium is suitable for receiving light having a wavelength of 850 nm or more. In this way, the wavelength that can be measured varies depending on the material.

  In addition to the above problem, there is also a problem that the threshold value may not be an appropriate criterion under artificial light or cloudy weather.

  In relation to the above, Patent Document 1 discloses an artificial light detection device that can identify day and night even when artificial lighting such as a streetlight exists in the surroundings. The artificial light detection device includes AC component detection means for detecting only the AC component of the electrical signal output from the optical sensor. Furthermore, a comparison means for comparing the detected AC component with a predetermined threshold value is provided. When the alternating current component is larger than the threshold value, it is determined that the light sensor is irradiated with artificial light, and the operation is switched to the night operation.

  In relation to the above, Patent Document 2 discloses a light control device for a liquid crystal display that automatically adjusts the brightness of the screen in accordance with the wavelength distribution characteristics of surrounding light sources. This light control device includes a plurality of optical sensors. A light sensor that matches the wavelength distribution characteristics of the light source is selected from a plurality of light sources and the brightness around the liquid crystal display is measured. Based on the measurement result, the inverter is intermittently operated to vary the brightness of the fluorescent tube. Thereby, the brightness of the screen is adjusted according to the ambient brightness.

JP 11-326043 A JP-A-11-135291

  However, since the technique of Patent Document 1 performs day and night recognition by threshold determination using an optical sensor, there is a problem in that the threshold determination accuracy decreases if there is wavelength dependency of the sensor, that is, variation. Further, the technique of Patent Document 2 is disadvantageous in terms of cost because it is necessary to add a plurality of optical sensors in accordance with the wavelength distribution characteristics.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a display device capable of improving the accuracy of day and night recognition irrespective of the wavelength dependence of an optical sensor.

  In order to achieve the above object, the display device of the present invention includes a display unit and an electrical signal obtained by performing spectral conversion of incident light for each wavelength, photoelectrically converting light for each wavelength obtained by the spectroscopy, and the photoelectric conversion. A ratio calculation unit that calculates a ratio of light energy of a plurality of predetermined wavelengths based on the distribution information in a display device including a spectral acquisition unit that generates distribution information indicating a distribution of light energy for each wavelength based on the distribution information And a display control unit for controlling the light emission amount of the display unit based on the ratio.

  According to this configuration, the display device of the present invention splits the incident light for each wavelength, photoelectrically converts the light for each wavelength obtained by spectroscopy, and for each wavelength based on the electrical signal obtained by photoelectric conversion. And a spectral acquisition unit that generates distribution information indicating the distribution of light energy. Moreover, the ratio calculation part which calculates the ratio of the light energy of several predetermined wavelength based on distribution information is provided. Moreover, the display control part which controls the light emission amount of a display part based on the calculated ratio is provided. Thereby, it is possible to perform light emission amount control according to the environment around the apparatus without requiring threshold determination of the light reception amount.

  In order to achieve the above object, the display device of the present invention includes a light source determination unit that determines a type of a light source of incident light based on the ratio calculated by the ratio calculation unit, and the display control unit includes The light emission amount of the display unit is controlled based on the determination result and the amount of light received by the spectral acquisition unit.

  According to this configuration, the display device of the present invention includes the light source determination unit that determines the type of the light source of the incident light based on the ratio calculated by the ratio calculation unit. The display control unit controls the light emission amount of the display unit based on the determination result and the light reception amount received by the spectral acquisition unit. Thereby, it is possible to perform light emission amount control according to the light source.

  In order to achieve the above object, in the display device of the present invention, the light source determination unit determines whether the incident light is natural light or artificial light based on the ratio calculated by the ratio calculation unit. The display control unit controls to increase the light emission amount of the display unit when the determination result indicates natural light, and reduces the light emission amount of the display unit when the determination result indicates artificial light. Control as follows.

  According to this configuration, the light source determination unit determines whether the incident light is natural light or artificial light based on the ratio calculated by the ratio calculation unit. The display control unit controls to increase the light emission amount of the display unit when the result of the determination indicates natural light. Further, when the determination result indicates artificial light, control is performed so as to reduce the light emission amount of the display unit. Avoid unnecessary increase in light emission at night.

  In order to achieve the above object, in the display device of the present invention, the display control unit performs color tone correction of an image displayed on the display unit based on the determination result.

  According to this configuration, the display control unit corrects the color tone of the image displayed on the display unit based on the determination result. Thereby, it is possible to perform color tone correction processing according to the light source.

  In order to achieve the above object, the display device of the present invention includes a recording unit that records the ratio calculated by the ratio calculation unit, and the display control unit calculates the ratio by the ratio calculation unit. If the difference between the calculated ratio and the previously calculated ratio recorded in the recording unit is compared, and the difference exceeds a predetermined value, the light emission amount of the display unit To control.

  According to this configuration, the display device of the present invention includes the recording unit that records the ratio calculated by the ratio calculating unit. The display control unit compares the difference between the calculated ratio and the previously calculated ratio recorded in the recording unit when the ratio calculation unit calculates the above ratio. When this difference exceeds a predetermined value, the light emission amount of the display unit is controlled. Thereby, only when the surrounding environment changes rapidly, the light emission amount is controlled.

  In order to achieve the above object, in the display device of the present invention, the display unit includes a backlight, and the display control unit controls the voltage applied to the backlight, thereby controlling the display unit. Control the amount of light emission.

  According to this configuration, the display unit is configured to include a backlight. The display control unit controls the amount of light emitted from the display unit by controlling the voltage applied to the backlight.

  In order to achieve the above object, in the display device of the present invention, the spectral acquisition unit can acquire a plurality of values by a CMOS (Complementary Metal Oxide Semiconductor) integrated circuit, a plurality of photodiodes, or a communication path. Is used to generate distribution information indicating the distribution of light energy for each wavelength of incident light.

  According to this configuration, the spectral acquisition unit includes a CMOS integrated circuit, a plurality of photodiodes, or a digital photosensor that can acquire a plurality of values by a communication path. Then, using this digital optical sensor, distribution information indicating the distribution of light energy for each wavelength of incident light is generated.

  In order to achieve the above object, in the display device of the present invention, the spectral acquisition unit splits incident light using a prism or a lens, and outputs light for each wavelength obtained by the spectroscopy to a plurality of light receiving elements. Photoelectric conversion is performed using the provided optical sensor array.

  According to this configuration, the spectral acquisition unit splits incident light using a prism or a lens. Then, the light for each wavelength separated is subjected to photoelectric conversion using an optical sensor array including a plurality of light receiving elements. Thereby, distribution information indicating the distribution of light energy for each wavelength of incident light is generated.

  According to the present invention, the light energy obtained from the incident light is not compared with the threshold value, but based on the ratio of the light energy of a plurality of wavelengths, it is determined whether the light is under natural light or artificial light. To do. Therefore, it is possible to identify the surrounding environment and adjust the light emission amount without being affected by the wavelength dependency of the sensor or the amount of incident light. Thereby, the visibility of a display part can be improved.

  In addition, according to the present invention, it is possible to prevent an unnecessary increase in the amount of light of the backlight under sunlight, which is advantageous in terms of power saving.

It is a block diagram which shows the apparatus structure of the display apparatus of this invention. It is a block diagram which shows the system configuration | structure of the navigation system containing the display apparatus of this invention. It is a functional block diagram which shows the structure of the function part with which the display apparatus of this invention is provided. It is a flowchart which shows the light reception ratio calculation process of this invention. It is a flowchart which shows the light emission amount control process of this invention. It is a table figure which shows an example of the environment discrimination | determination table of this invention. It is a graph which shows the spectral distribution of sunlight. It is a graph which shows the spectral distribution of a fluorescent lamp. It is a schematic diagram which shows an example of a spectrum acquisition part. It is a graph which shows the characteristic of an optical sensor.

Embodiments of the present invention will be described below with reference to the drawings. In addition, embodiment shown here is an example and this invention is not limited to embodiment shown here.
<1. About the configuration of the display device>

  FIG. 1 is a block diagram showing an internal configuration of a portable navigation 100 (= display device) according to an embodiment of the present invention. The portable navigation 100 of this embodiment is an electronic device that is mounted on the vehicle 1 and forms part of the navigation system.

  FIG. 2 is a block diagram showing a configuration of a navigation system including the portable navigation 100. The navigation system is configured to include at least a vehicle 1 and a GPS (Global Positioning System) satellite 2.

  The vehicle 1 is a moving body on which a portable navigation 100 is mounted. The GPS satellite 2 is arranged on the satellite orbit and transmits a specific radio wave (for example, an L1 radio wave of 1.575 GHz) to the ground GPS receiver. Thereby, various information for calculating the position information, for example, coordinate information of the GPS satellite 2, time information for measuring the propagation time of the radio wave, and the like are transmitted.

  As shown in the block diagram of FIG. 1, the portable navigation 100 includes at least a control unit 10, a GPS antenna 20, a positioning navigation device 21, an LCD (Liquid Crystal Display) 30 (= display unit), a backlight 31, a touch panel 32, a speaker. 40, a multi-light sensor 50 (= digital light sensor, spectral acquisition unit), a RAM 60, a ROM 61, and a flash memory 62 (= recording unit).

  The control unit 10 organically controls driving of each member of the portable navigation 100, and performs overall control of position information acquisition processing, display processing, and the like. In addition, the control unit 10 includes a wavelength level detection unit 11 to a display control unit 13 (FIG. 3) as functional units realized by executing a predetermined program on the arithmetic processing device included in the control unit 10. Details of processing performed by each functional unit will be described later.

  The GPS antenna 20 is a receiver for receiving a specific radio wave (for example, an L1 radio wave of 1.575 GHz) emitted from the GPS satellite 2. The GPS antenna 20 can receive a signal including coordinate information of each GPS satellite 2 from a plurality of GPS satellites 2.

  The positioning navigation device 21 is a device that includes a positioning device that decodes a signal received by the GPS antenna 20 to generate latitude and longitude information, and a navigation device that generates speed information and attitude angle information by a gyro and a vehicle speed sensor.

  The LCD 30 is a display device including a liquid crystal panel and a driver, and includes a backlight 31 behind it. The driver decodes the image data sent from the control unit 10 and applies a driving voltage to each pixel electrode of the liquid crystal panel. Receiving this, the liquid crystal panel displays an image based on the applied drive voltage. As a result, various information held by the portable navigation 100, such as traffic information and a menu screen, can be displayed.

  The backlight 31 is a light emitting device arranged on the back side of the liquid crystal panel. As the backlight 31, for example, an edge light system using a cold cathode tube as a light source or a direct type system in which fluorescent lamps are arranged on the back surface of a liquid crystal panel is used. The amount of light emitted from the light source of the backlight 31 is controlled by the display controller 13 described later.

  The touch panel 32 is an operation device that is attached to the front of the display screen of the LCD 30. When the driver of the vehicle 1 performs a touch operation on the display area to which the touch panel 32 is attached, a control instruction corresponding to the operation position coordinates is generated and given to the control unit 10.

  The speaker 40 is an audio output device that outputs audio including various information to a passenger of the vehicle 1. The speaker 40 is used, for example, to output a guidance voice or a warning voice in navigation processing.

  The multi-light sensor 50 is a digital light sensor including a plurality of wires and an SMBus (System Management Bus) serial interface. The multi-light sensor 50 combines two photodiodes and a companding AD converter on a CMOS integrated circuit in order to perform 12-bit dynamic range light measurement.

  Thereby, the multi-light sensor 50 acquires distribution information indicating a spectral distribution for each wavelength of incident light. For example, FIG. 7 shows an example of a spectral distribution of sunlight, and FIG. 8 shows an example of a spectral distribution of a fluorescent lamp. As the multi-light sensor 50, for example, an ambient light sensor (TSL2550 or the like) manufactured by TAOS (http://www.taosinc.com) is used.

  The RAM 60 is a readable / writable recording medium that temporarily records processing data when the control unit 10 performs various processes. For example, the contents of the user operation detected by the touch panel 32, each setting item set based on the user operation, and the like are recorded.

  The ROM 61 is a read-only recording medium that records information that is not rewritten by the user, such as programs and various setting information at the time of shipment from the factory. ROM 61 stores, for example, a firmware program executed by the control unit 10.

The flash memory 62 is a recording medium for recording information having a relatively large data size. The flash memory 62 is used for recording, for example, a map database used for navigation processing, audio information for outputting audio from the speaker 40, and the like.
<2. About the light reception ratio calculation process>

  Here, an outline of the light reception ratio calculation process performed by the portable navigation 100 according to the embodiment of the present invention will be described with reference to the flowchart of FIG. The processing flow shown in FIG. 4 is started when the portable navigation 100 is in an operating state. Further, it is assumed that this process is repeatedly executed at a predetermined cycle, for example, one second cycle as long as the portable navigation 100 is in an operating state.

  After the start of this process, the light reception ratio calculation unit 11b (= ratio calculation unit) acquires a wavelength level of 550 nm (= a signal level indicating the amount of received light for each wavelength) using the multi-light sensor 50 in step S110. Then, the obtained value is substituted into the variable LV550R.

  Next, in step S120, the light reception ratio calculation unit 11b corrects the value of LV550R in accordance with the sensitivity for each wavelength of the multi-light sensor 50. Then, the corrected value is substituted into the variable LV550C.

  Next, the light reception ratio calculation unit 11b acquires the wavelength level of 700 nm using the multi-light sensor 50 in step S130. Then, the acquired value is substituted into the variable LV700R.

  Next, in step S140, the light reception ratio calculation unit 11b corrects the value of the LV 700R according to the sensitivity for each wavelength of the multi-light sensor 50. Then, the corrected value is substituted into the variable LV700C.

  Note that the wavelengths to be detected (550 nm and 700 nm in the above example) can be changed by the detection wavelength setting unit 11a. The detection wavelength setting unit 11a receives the wavelength to be detected using the touch panel 32 or the like. The received value is recorded in the flash memory 62. The light reception ratio calculation unit 11b refers to this value and performs Steps S110 to S140.

Next, in step S150, the light reception ratio calculation unit 11b calculates the light reception ratio. Specifically, as shown in the following calculation formula, a value obtained by dividing LV550C by LV700C is defined as a light reception ratio Ratio.
Ratio = LV550C ÷ LV700C

  Next, in step S160, the light reception ratio calculation unit 11b compares the difference between a variable Ratio_bak described later and the ratio calculated above. Then, it is determined whether or not this difference is within a predetermined value (1 in the present embodiment).

  If no value is assigned to Ratio_bak, step S160 is skipped and the process proceeds to step S170. Alternatively, the above comparison may be performed after a predetermined default value is substituted into Ratio_bak.

  As a result of the determination, if it is within 1, the light reception ratio calculating unit 11b substitutes the value of Ratio into Ratio_bak in step S170, and then ends this process.

As a result of the determination, if it exceeds 1, the light reception ratio calculation unit 11b transmits a notification (hereinafter referred to as “ratio change event”) indicating that a ratio change has occurred to the display control unit 13 in step S165. When the transmission is completed, the process is terminated after the process proceeds to step S170.
<3. About the light emission control process>

  Here, an outline of the light emission amount control processing performed by the portable navigation 100 according to the embodiment of the present invention will be described with reference to the flowchart of FIG. The processing flow shown in FIG. 5 is started when the portable navigation 100 is in an operating state.

  After the start of this process, in step S210, the display control unit 13 determines whether or not the above-described ratio change event has been received from the light reception ratio calculation unit 11b. If not received, the process proceeds to step S210 again and waits for reception. When the ratio change event is received, the process proceeds to the next step S220.

  Next, in step S220, the display control unit 13 instructs the day / night determination unit 12 (= light source determination unit) to perform day / night determination processing. Receiving this, the day / night determination unit 12 measures the amount of received light using the multi-light sensor 50.

  Next, in step S230, the day / night determination unit 12 performs day / night determination processing based on the measured amount of received light and the ratio value indicated in the ratio change event. Specifically, for example, the determination is performed using the environment determination table shown in FIG.

  As shown in FIG. 6, when the amount of received light is 10 mV or more and the ratio is less than 3, it is determined that daytime sunlight (= natural light) is received. When the amount of received light is 10 mV or more and the ratio is 3 or more, it is considered that a nighttime fluorescent lamp (= artificial light) is received. When the amount of received light is less than 10 mV, it is determined that it is nighttime regardless of Ratio.

  In addition, said value is an example to the last, and it is also possible to change said value suitably in the range which does not deviate from the meaning of this invention.

  Next, in step S240, the process is branched based on the determination result. When the determination result is daytime, the display control unit 13 controls the backlight 31 so as to increase the light emission amount by a predetermined value in step S250. When the determination result is nighttime, the display control unit 13 controls the backlight 31 so as to reduce the light emission amount by a predetermined value in step S255.

  When the process of step S250 or step S255 is completed, the process proceeds to step S210 again, and continuously waits for a ratio change event. It is assumed that the above processing flow is continuously performed until the portable navigation 100 cannot be executed, for example, because the power of the portable navigation 100 is stopped.

  The present embodiment described above utilizes the fact that the ratio between the wavelength level near 780 nm and the wavelength level near 550 nm differs greatly between sunlight and fluorescent lamps. Under sunlight, the ratio of both wavelength levels is approximately 2: 1 as shown in FIG.

  Based on this relationship and the correlation between the sensitivity distributions of the multi-light sensor 50, it is determined whether or not it is under sunlight. In the case of sunlight, PWM control is performed according to all received light amounts received by the multi-light sensor 50, and the light emission amount of the backlight 31 is adjusted.

On the other hand, under a fluorescent lamp, there is almost no infrared light as shown in FIG. 8, and the wavelength level around 550 nm is extremely large. Therefore, with this characteristic, it is determined that the lamp is under a fluorescent lamp. When it is under a fluorescent lamp, the backlight 31 is controlled so that the light emission amount can be recognized by the LCD 30 under general illumination. Thereby, the light emission amount adjustment suitable for the periphery of the portable navigation 100 can be performed.
[Other embodiments]

  The present invention has been described with reference to the preferred embodiments and examples. However, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea. be able to.

  Therefore, the present invention can also be applied to the following embodiments.

  (A) In the above embodiment, each functional unit related to the light reception ratio calculation process and the light emission amount control process of the present invention is realized by executing a predetermined program on an arithmetic processing unit such as a microprocessor. Various functional units may be realized by a plurality of circuits.

  (B) In the above embodiment, the portable navigation 100 has been described as an example of a display device that performs the light reception ratio calculation process and the light emission amount control process of the present invention, but the present invention may be implemented in other display devices. . For example, it may be implemented in a mobile phone, a PDA, a portable TV, a large outdoor liquid crystal display, or the like.

  (C) In the above embodiment, the light reception ratio Ratio is calculated by comparing the wavelength level of 550 nm and the wavelength level of 700 nm. However, the wavelength to be compared is not limited to the above, and the gist of the present invention. As long as it does not deviate from the above, it can be appropriately changed.

  (D) In the above embodiment, the multi-light sensor 50 has been described as an example of the spectral acquisition unit, but a spectral acquisition unit made of other members may be used. For example, as shown in FIG. 9, the wavelength of incident light is separated by a prism 90, light of each wavelength is received by an encoder photo IC 91 (= photo sensor array) and converted into a signal, thereby obtaining a spectral distribution. But you can. The encoder photo IC 91 is configured by arranging a plurality of optical sensors so that light of each wavelength is irradiated to the optical sensors corresponding to the respective wavelengths.

  (E) In the above embodiment, the light emission amount control process is performed based on the result of the light reception ratio calculation process. However, other processes may be performed based on the result of the light reception ratio calculation process. For example, the color tone correction process for the image displayed on the LCD 30 may be implemented based on the result of the light reception ratio calculation process.

1 Vehicle 2 GPS Satellite 100 Portable Navigation (Display Device)
DESCRIPTION OF SYMBOLS 10 Control part 11 Wavelength level detection part 11a Detection wavelength setting part 11b Light reception ratio calculation part (ratio calculation part)
12 Day / night discriminator (light source discriminator)
13 Display Control Unit 20 GPS Antenna 21 Positioning Navigation Device 30 LCD (Display Unit)
31 Backlight 32 Touch panel 40 Speaker 50 Multi-light sensor (spectral acquisition unit, digital optical sensor)
60 RAM
61 ROM
62 Flash memory (recording unit)
90 Prism 91 Photo IC for encoder (photo sensor array)

Claims (8)

A display unit;
Spectral acquisition that splits incident light for each wavelength, photoelectrically converts light for each wavelength obtained by the spectrum, and generates distribution information indicating the distribution of light energy for each wavelength based on the electrical signal obtained by the photoelectric conversion A display device comprising:
A ratio calculation unit that calculates a ratio of light energy of a plurality of predetermined wavelengths based on the distribution information;
A display control unit configured to control a light emission amount of the display unit based on the ratio. A light source discriminating unit that discriminates the type of the light source of the incident light based on the ratio calculated by the ratio calculating unit;
The display control unit controls a light emission amount of the display unit based on a result of the determination and a light reception amount received by the spectral acquisition unit;
The display device according to claim 1. The light source determination unit determines whether the incident light is natural light or artificial light based on the ratio calculated by the ratio calculation unit;
The display control unit controls to increase the light emission amount of the display unit when the determination result indicates natural light, and reduces the light emission amount of the display unit when the determination result indicates artificial light. Control,
The display device according to claim 2. The display control unit performs color tone correction of an image displayed by the display unit based on the determination result;
The display device according to claim 2. A recording unit for recording the ratio calculated by the ratio calculating unit;
When the ratio is calculated by the ratio calculation unit, the display control unit compares the difference between the calculated ratio and the previously calculated ratio recorded in the recording unit, and the difference Controls the amount of light emitted from the display unit when the value exceeds a predetermined value;
The display device according to claim 1. The display unit includes a backlight;
The display control unit controls the amount of light emitted from the display unit by controlling a voltage applied to the backlight;
The display device according to claim 1. The spectral acquisition unit shows a distribution of light energy for each wavelength of incident light by using a CMOS (Complementary Metal Oxide Semiconductor) integrated circuit, a plurality of photodiodes, or a digital photosensor capable of acquiring a plurality of values by a communication path. Generate distribution information,
The display device according to claim 1.   The said spectrum acquisition part spectrally divides incident light using a prism or a lens, and photoelectrically converts the light for every wavelength obtained by the said spectroscopy using a photosensor array provided with a some light receiving element. Display device.

Images