Patent Application
20180364523
The present invention relates to a light-emitting apparatus, a display apparatus, and an information-processing apparatus.
In a liquid crystal display apparatus, unintended variation occurs in the emission color, emission brightness, and so on of a backlight unit due to variation in the temperature of the backlight unit, deterioration of the backlight unit, and so on. As a result of this unintended variation in the emission color, emission brightness, and so on of the backlight unit, unintended variation occurs in the display color, display brightness, and so on of the liquid crystal display apparatus.
Here, the backlight unit may include a white LED (an LED that emits white light) as a light source unit (a light source). A white LED is structured such that an LED chip and a fluorescent material are provided in an LED package. The LED chip emits excitation light (blue light or the like). The fluorescent material is provided on the LED chip so as to emit fluorescence (yellow light, red light, green light, or the like) when irradiated with the excitation light. Hence, the emission color of the white LED is determined by a combination of an emission characteristic of the LED chip and an emission characteristic of the fluorescent material. Variation in the emission characteristic due to variation in the temperature of the backlight unit, deterioration of the backlight unit, and so on typically differs between the LED chip and the fluorescent material. As a result, unintended variation in the emission color of the light source unit or the like occurs due to variation in the temperature of the backlight unit, deterioration of the backlight unit, and so on.
In a liquid crystal display apparatus, control may be executed to suppress the unintended variation described above. The backlight unit may include a large number of light source units (for example, several hundred LEDs). Further, to reduce the cost of the liquid crystal display apparatus, a small number (several tens, for example) of inexpensive brightness sensors are typically provided in the liquid crystal display apparatus as sensors used during the aforesaid control. In conventional control, the emission brightness of the light source unit is detected using the brightness sensor, and unintended variation in the display brightness is suppressed on the basis of a detection value of the emission brightness.
However, the brightness sensor cannot detect the emission color of the light source unit, and therefore, in the conventional control described above, unintended variation in the display color is not suppressed on the basis of the detection value of the emission brightness of the light source unit. To suppress unintended variation in the display color, a colorimeter capable of detecting the display color is used. However, using a colorimeter leads to a large increase in the cost of the control.
A high color-rendering white LED (a delayed luminescence type LED) may be used as the light source unit of the backlight unit in order to widen the color gamut of the emission color of the backlight unit, the display color of the liquid crystal display apparatus, and so on. In a delayed luminescence type LED, cyan light is emitted in response to supply of a drive signal (a current, a voltage, or the like) to the delayed luminescence type LED, whereupon red light (red fluorescence) is emitted at a delay. By time-integrating the cyan light and the red light, white light is realized as the emission color of the delayed luminescence type LED.
Japanese Patent Application Publication No. 2013-73803, for example, discloses a conventional technique relating to the detection of light emitted from a light source unit. In the technique disclosed in Japanese Patent Application Publication No. 2013-73803, a brightness sensor detects the brightness of light emitted from an LED at each of two predetermined timings within a period in which a drive current is applied to the light source unit. Then, on the basis of the two detection values obtained using the brightness sensor, feedback control is executed to keep the brightness of the light emitted from the LED constant.
However, when the technique disclosed in Japanese Patent Application Publication No. 2013-73803 is used on a backlight unit having a delayed luminescence type LED, a detection value of light other than white light may be obtained mistakenly from the brightness sensor as the detection value of the white light. For example, a detection value of the cyan light, which is detected during a period in which only the cyan light is emitted, may be obtained mistakenly as the detection value of the white light. Further, a detection value of the red light, which is detected during a period in which only the red light is emitted, may be obtained mistakenly as the detection value of the white light. Hence, a detection value of the light emitted from the delayed luminescence type LED cannot be obtained from the brightness sensor with a high degree of precision. Moreover, the emission color of the delayed luminescence type LED cannot be determined from the obtained detection value.
The present invention in its first aspect provides a light-emitting apparatus comprising:
a light source configured to emit light of a first color in response to input of a drive signal, and emit light of a second color that is different from the first color after a predetermined time elapses following emission of the light of the first color;
a setting unit configured to set a first detection period for detecting a brightness of the light of the first color within a period during which the drive signal is input into the light source, and set a second detection period for detecting a brightness of the light of the second color within a period during which the drive signal is not input into the light source; and
a detecting unit configured to obtain a detection value corresponding to the brightness of the light emitted from the light source during each of the set first and second detection periods.
The present invention in its second aspect provides an information-processing apparatus configured to obtain information relating to a light-emitting apparatus having a light source configured to emit light of a first color in response to input of a drive signal and emit light of a second color that is different from the first color after a predetermined time elapses following emission of the light of the first color, and a brightness sensor configured to measure a brightness of the light emitted from the light source,
the information-processing apparatus comprising:
a setting unit configured to set a first detection period for detecting a brightness of the light of the first color within a period during which the drive signal is input into the light source, and set a second detection period for detecting a brightness of the light of the second color within a period during which the drive signal is not input into the light source; and
a detecting unit configured to obtain a detection value corresponding to the brightness of the light emitted from the light source during each of the set first and second detection periods.
The present invention in its third aspect provides a display apparatus comprising:
a light source configured to emit light of a first color in response to input of a drive signal, and emit light of a second color that is different from the first color after a predetermined time elapses following emission of the light of the first color;
a display unit configured to display an image by transmitting the light emitted from the light source on the basis of display image data;
a setting unit configured to set a first detection period for detecting a brightness of the light of the first color within a period during which the drive signal is input into the light source, and set a second detection period for detecting a brightness of the light of the second color within a period during which the drive signal is not input into the light source; and
a detecting unit configured to obtain a detection value corresponding to the brightness of the light emitted from the light source during each of the set first and second detection periods.
The present invention in its fourth aspect provides a control method for a light-emitting apparatus having a light source configured to emit light of a first color in response to input of a drive signal, and emit light of a second color that is different from the first color after a predetermined time elapses following emission of the light of the first color, and a brightness sensor configured to measure a brightness of the light emitted from the light source,
the control method comprising:
a setting step of setting a first detection period for detecting a brightness of the light of the first color within a period during which the drive signal is input into the light source, and setting a second detection period for detecting a brightness of the light of the second color within a period during which the drive signal is not input into the light source; and
a detecting step of obtaining a detection value corresponding to the brightness of the light emitted from the light source during each of the set first and second detection periods.
The present invention in its fifth aspect provides a control method for a display apparatus having a light source configured to emit light of a first color in response to input of a drive signal and emit light of a second color that is different from the first color after a predetermined time elapses following emission of the light of the first color, a display unit configured to display an image by transmitting the light emitted from the light source on the basis of display image data, and a brightness sensor configured to measure a brightness of the light emitted from the light source,
the control method comprising:
a setting step of setting a first detection period for detecting a brightness of the light of the first color within a period during which the drive signal is input into the light source, and setting a second detection period for detecting a brightness of the light of the second color within a period during which the drive signal is not input into the light source; and
a detecting step of obtaining a detection value corresponding to the brightness of the light emitted from the light source during each of the set first and second detection periods.
The present invention in its sixth aspect provides a non-transitory computer readable medium that stores a program, wherein the program causes a computer to execute the above mentioned control method.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
A first embodiment of the present invention will be described below. An information-processing apparatus according to this embodiment is an apparatus for obtaining information relating to a light-emitting apparatus.
An example in which the light-emitting apparatus includes the information-processing apparatus will be described below. The light-emitting apparatus is a streetlamp, an indoor light, a microscope light, a flashlight, a household electric appliance, an in-vehicle apparatus, or the like, for example.
Note that the information-processing apparatus may be provided separately to the light-emitting apparatus. For example, the information-processing apparatus may be a personal computer (PC), a PDA, a tablet terminal, a mobile telephone terminal (including a smartphone), a household electric appliance, an in-vehicle apparatus, or the like provided separately to the light-emitting apparatus.
Configuration of Light-Emitting Apparatus
An example configuration of the light-emitting apparatus according to this embodiment will now be described.
A light source control signal is input into the light source unit 101. The light source unit 101 starts to emit a plurality of light beams corresponding respectively to a plurality of color components at a plurality of different timings in response to a lighting instruction included in the light source control signal. More specifically, the light source unit 101 starts to emit light corresponding to a first color at a first timing corresponding to the lighting instruction, and starts to emit light corresponding to a second color at a second timing following the elapse of a predetermined time after the first timing. In this embodiment, the first color and the second color correspond respectively to two color components constituting white. More specifically, the first color is cyan and the second color is red.
In this embodiment, the light source unit 101 is constituted by a single light-emitting element such as a high color-rendering white LED (a delayed luminescence type LED). A delayed luminescence type LED is structured such that an LED chip and a fluorescent material are provided in an LED package. The LED chip emits excitation light (cyan light, blue light, or the like). The fluorescent material is provided on the LED chip so as to emit fluorescence (yellow light, red light, green light, or the like) when irradiated with the excitation light. Hence, the emission color of the delayed luminescence type LED is determined by a combination of an emission characteristic of the LED chip and an emission characteristic of the fluorescent material. In the delayed luminescence type LED according to this embodiment, cyan light is emitted in response to supply of a drive signal (a current, a voltage, or the like) to the delayed luminescence type LED, whereupon red light (red fluorescence) is emitted at a delay. More specifically, the LED chip emits cyan light as the excitation light, and the fluorescent material emits red light as the fluorescence. By time-integrating the cyan light and the red light, white light is realized as the emission color of the delayed luminescence type LED. Further, a certain amount of time is required for the fluorescent material to emit red light after the cyan light emitted by the LED enters the fluorescent material. The reason for this is believed to be that a fluorescent material emits light after first absorbing energy exerted thereon so as to trap electrons or holes.
In this embodiment, a time difference between the timing at which cyan light emission (emission of the cyan light) starts and the timing at which red light emission (emission of the red light) starts is set as a delay time. The delay time is determined according to characteristics of the fluorescent material of the delayed luminescence type LED. Further, the light source control signal is a pulse width modulation signal for controlling the timing at which the LED is lit. Cyan light is emitted from the LED for a lighting period specified by the light source control signal. By controlling the light source control signal, light emission by the light source unit 101 can be controlled.
Note that the first color is not limited to cyan and the second color is not limited to red. The plurality of emitted light beams are not limited to two light beams corresponding respectively to two color components, and three or more light beams corresponding respectively to three or more color components may be emitted. The light source unit 101 may include a plurality of light-emitting elements. The light-emitting element is not limited to a delayed luminescence type LED having an LED (a light-emitting diode) and a fluorescent material. For example, an organic electro-luminescence (EL) element, a laser light source, a cold cathode ray tube, or the like may be used as the light-emitting element instead of an LED. The light-emitting apparatus may include a plurality of light source units.
The delay information storage unit 102 stores delay information in advance. The delay information is information relating to the delay time of each of the plurality of emitted light beams. The delay time is a time following the emission start timing of the light beam, among the plurality of emitted light beams, that is emitted earliest, a time following the timing of the lighting instruction, or the like, for example. In this embodiment, the delay information denotes a time extending from the timing at which cyan light emission (emission of the cyan light) is started to the timing at which red light emission (emission of the red light) is started as the delay time. In other words, the delay information denotes the aforesaid predetermined time. A semiconductor memory, a magnetic disc, an optical disc, or the like, for example, is used as the delay information storage unit 102. Note that the delay information storage unit 102 may be a storage apparatus that can be attached to and detached from the light-emitting apparatus.
There are no particular limitations on the format of the delay information, but in this embodiment, the delay information storage unit 102 stores delay table data as table data including the delay information. The delay time of the light source unit 101 is assumed to be 10 msec, for example.
The detection timing control unit 103 sets a period in which only light of a target component, among the plurality of color components (cyan and red), is emitted from the light source unit 101 as a detection period. In this embodiment, the detection timing control unit 103 reads the delay information from the delay information storage unit 102. Further, the light source control signal is input into the detection timing control unit 103. The detection timing control unit 103 then sets the detection period on the basis of the delay information and the light source control signal. More specifically, the detection timing control unit 103 generates a sensor detection control signal so that the brightness sensor 104 implements detection during the period in which only light of the target component is emitted from the light source unit 101, and outputs the sensor detection control signal to the brightness sensor 104. In other words, the detection timing control unit 103 sets a cyan light detection period within a period in which only cyan light is emitted. Further, the detection timing control unit 103 sets a red light detection period within a period in which only red light is emitted. The sensor detection control signal is generated on the basis of the delay information and the light source control signal.
Note that as long as a detection value (a sensor value) corresponding to a brightness detected by the brightness sensor 104 during the detection period is obtained by the color variation determination unit 107, the brightness sensor 104 may also implement detection outside the detection period.
The brightness sensor 104 detects the brightness of the light emitted from the light source unit 101, and outputs a sensor value corresponding to the detected brightness to the color variation determination unit 107. In this embodiment, the sensor detection control signal is input into the brightness sensor 104. The brightness sensor 104 then executes the processing described above in accordance with the sensor detection control signal. In other words, the brightness sensor 104 detects the brightness of the light emitted from the light source unit 101 during the detection period, and outputs a sensor value corresponding to the detected brightness to the color variation determination unit 107.
The reference sensor value storage unit 105 stores a reference sensor value (a reference value of the sensor value) in advance. The reference sensor value is a fixed value determined in advance by a manufacturer, a value that is periodically updated automatically in the light-emitting apparatus, a value specified by a user, or the like, for example. More specifically, the reference sensor value is a sensor value or the like obtained when the emission color of the light source unit 101 is white. A semiconductor memory, a magnetic disc, an optical disc, or the like, for example, is used as the reference sensor value storage unit 105. Note that the reference sensor value storage unit 105 may be a storage apparatus that can be attached to and detached from the light-emitting apparatus. The emission color may also be referred to as “a color perceived by a user when the user sees the light emitted from the light source unit 101”, “a color of output light realized by time-integrating the plurality of light beams corresponding respectively to the plurality of color components”, and so on.
The color relationship information storage unit 106 stores color relationship information in advance. The color relationship information denotes a correspondence relationship between the sensor value and a color-related value relating to the emission color of the light source unit 101. The color relationship information is information generated using a colorimeter or the like, fixed information set in advance by the manufacturer, information that is periodically updated automatically in the light-emitting apparatus, information specified by the user, or the like, for example. A semiconductor memory, a magnetic disc, an optical disc, or the like, for example, is used as the color relationship information storage unit 106. Note that the color relationship information storage unit 106 may be a storage apparatus that can be attached to and detached from the light-emitting apparatus.
The color variation determination unit 107 obtains the sensor value corresponding to the brightness detected by the brightness sensor 104 during the detection period from the brightness sensor 104 as a sensor value corresponding to the target component. Here, a case in which a plurality of detection periods corresponding respectively to a plurality of target components are set will be considered. In this case, the color variation determination unit 107 obtains a sensor value corresponding to the brightness detected by the brightness sensor 104 during the detection period corresponding to the target component from the brightness sensor 104 as the sensor value corresponding to the target component for each of the plurality of target components. For example, a sensor value corresponding to the brightness detected by the brightness sensor 104 during the detection period corresponding to cyan is obtained from the brightness sensor 104 as the sensor value corresponding to cyan. Further, a sensor value corresponding to the brightness detected by the brightness sensor 104 during the detection period corresponding to red is obtained from the brightness sensor 104 as the sensor value corresponding to red.
Furthermore, in this embodiment, the color variation determination unit 107 determines a value (emission color information) relating to the emission color of the light source unit 101 on the basis of the obtained sensor value (a current sensor value). More specifically, the color variation determination unit 107 determines an emission color value indicating the emission color (the current emission color) of the light source unit 101 on the basis of the current sensor value and the color relationship information. The color variation determination unit 107 then determines a color variation value indicating a difference between the emission color (the current emission color) of the light source unit 101 and a predetermined emission color on the basis of the emission color value, the reference sensor value, and the color relationship information.
Note that either the emission color value or the color variation value alone may be determined as the value relating to the emission color of the light source unit 101. Further, a different value from the emission color value and the color variation value may be determined as the value relating to the emission color of the light source unit 101. The color variation determination unit 107 may output the obtained sensor value to another apparatus in association with the corresponding color component. The value relating to the emission color of the light source unit 101 may then be determined by the other apparatus.
Detection Period Setting Method
A specific example of a method for setting the detection period will now be described using
The detection timing control unit 103 obtains the delay information and the light source control signal. In
The detection timing control unit 103 then generates the sensor detection control signal on the basis of the delay information and the light source control signal. A reference numeral 406 in
The sensor detection control signal 406 in
Color Variation Value Determination Method
A specific example of a method for determining the color variation value will now be described using
Step 1-1
In step 1-1, the color variation determination unit 107 obtains the sensor value YC detected by the brightness sensor 104 during the detection period D1 from the brightness sensor 104. The sensor value YC corresponds to the brightness of the cyan light. Further, the color variation determination unit 107 obtains the sensor value YR detected by the brightness sensor 104 during the detection period D2 from the brightness sensor 104. The sensor value YR corresponds to the brightness of the red light. The color variation determination unit 107 then determines the XYZ tristimulus values (the X stimulus value, the Y stimulus value, and the Z stimulus value)=(KX, KY, KZ) as an emission color value indicating the emission color (the current emission color) of the light source unit 101 on the basis of the sensor values YR, YC and the color relationship table data. More specifically, the color variation determination unit 107 obtains the X stimulus value KX corresponding to the detected sensor value YR from the color relationship table data. The color variation determination unit 107 then obtains the Y stimulus value KY corresponding to the sum of the detected sensor value YR and the detected sensor value YC from the color relationship table data. The color variation determination unit 107 then obtains the Z stimulus value KZ corresponding to the detected sensor value YC from the color relationship table data.
Note that the color-related values corresponding to the obtained sensor values YR, YC may not be shown in the color relationship table data. In this case, the color-related values corresponding to the obtained sensor values may be determined by, for example, interpolation processing using the plurality of color-related values shown in the color relationship table data.
Step 1-2
In step 1-2, the color variation determination unit 107 obtains information indicating the reference emission color. The information indicating the reference emission color is constituted by XYZ tristimulus values (CX, CY, CZ) denoting the reference emission color (the predetermined emission color). Note that the color variation determination unit 107 may obtain the information indicating the reference emission color on the basis of reference sensor values CR, CC obtained from the reference sensor value storage unit 105 and the color relationship table data. The reference sensor value CR is a reference value of the sensor value of the red light, and the reference sensor value CC is a reference value of the sensor value of the cyan light.
Step 1-3
In step 1-3, the color variation determination unit 107 determines a color variation value indicating a difference between the emission color (the current emission color) of the light source unit 101 and the reference emission color on the basis of the XYZ tristimulus values (KX, KY, KZ), (CX, CY, CZ) obtained in steps 1-1 and 1-2. In this embodiment, the color variation determination unit 107 determines an X variation value DX indicating a difference between the X stimulus value KX and the X stimulus value CX, a Y variation value DY indicating a difference between the Y stimulus value KY and the Y stimulus value CY, and a Z variation value DZ indicating a difference between the Z stimulus value KZ and the Z stimulus value CZ. More specifically, as shown below in formula 1, the color variation determination unit 107 calculates the X variation value DX by dividing the X stimulus value KX by the X stimulus value CX. Further, as shown below in formula 2, the color variation determination unit 107 calculates the Y variation value DY by dividing the Y stimulus value KY by the Y stimulus value CY. Further, as shown below in formula 3, the color variation determination unit 107 calculates the Z variation value DZ by dividing the Z stimulus value KZ by the Z stimulus value CZ.
DX=KX/CX (formula 1)
DY=KY/CY (formula 2)
DZ=KZ/CZ (formula 3)
In this embodiment, an example in which values based on XYZ tristimulus values are determined as values (the emission color value, the color variation value, and so on) relating to the emission color of the light source unit 101 was described, but the present invention is not limited thereto. For example, values based on u′ and v′ chromaticity values (a u′ chromaticity value and a v′ chromaticity value) may be determined as values relating to the emission color of the light source unit 101. By employing a u′ chromaticity value and a v′ chromaticity value respectively as color-related values, values based on the u′ and v′ chromaticity values (u′ and v′ chromaticity coordinates) can be determined as values relating to the emission color of the light source unit 101. Values based on x and y chromaticity values (an x chromaticity value and a y chromaticity value) can also be determined as values relating to the emission color of the light source unit 101. By employing an x chromaticity value and a y chromaticity value respectively as color-related values, values based on the x and y chromaticity values (x and y chromaticity coordinates) can be determined as values relating to the emission color of the light source unit 101. Moreover, a value based on at least one of an X stimulus value, a Y stimulus value, a Z stimulus value, a u′ chromaticity value, a v′ chromaticity value, an x chromaticity value, and a y chromaticity value may be determined as a value relating to the emission color of the light source unit 101.
Further, in this embodiment, an example in which table data (color relationship table data) are used as the color relationship information was described, but the present invention is not limited thereto. For example, a function or the like indicating a correspondence relationship between the sensor value and the color-related value may be used as the color relationship information.
Furthermore, typically, the X stimulus value of light has a high correlation with the red component of the light, the Y stimulus value of light has a high correlation with the sum of the red component and the cyan component of the light, and the Z stimulus value of light has a high correlation with the cyan component of the light. In this embodiment, therefore, an example in which the sensor value R is associated with the X stimulus value, the sum of the sensor value R and the sensor value C is associated with the Y stimulus value, and the sensor value C is associated with the Z stimulus value was described. However, the correspondence relationship between the sensor value and the color-related value is not limited to this example, and instead, for example, the correspondence relationship between the sensor value and the color-related value may be determined on the basis of the sensor value and a measurement value of the emission color of the light source unit 101. Further, the sensor value R may be associated with the X stimulus value, and the sensor value C may be associated with the Y stimulus value and the Z stimulus value.
Furthermore, in this embodiment, an example in which the value relating to the emission color of the light source unit 101 is determined on the basis of the sensor value obtained from the brightness sensor 104 was described, but the present invention is not limited thereto, and instead, for example, an emission brightness or the like of the light source unit 101 may be determined on the basis of the sensor value of the cyan light and the sensor value of the red light. The emission brightness may also be referred to as “a brightness perceived by a user when the user sees the light emitted by the light source unit 101”, “a brightness of output light realized by time-integrating the plurality of light beams corresponding respectively to the plurality of color components”, and so on.
Moreover, in this embodiment, an example in which a cyan light detection period and a red light detection period are set was described, but the present invention is not limited thereto, and instead, for example, a cyan light detection period may be set alone. By setting the cyan light detection period, the sensor value YC can be obtained as the sensor value of the cyan light, and as a result, the Z stimulus value KZ, the Z variation value DZ, and so on can be determined. Further, a red light detection period may be set alone. By setting the red light detection period, the sensor value YR can be obtained as the sensor value of the red light, and as a result, the X stimulus value KX, the X variation value DX, and so on can be determined.
Another specific example of a method for setting the detection period will now be described using
Effects
According to this embodiment, as described above, a period in which only light of a target component is emitted from the light source unit is set as a detection period. A sensor value corresponding to the brightness detected by the brightness sensor during the detection period is then obtained from the brightness sensor as a sensor value corresponding to the target component. Hence, a sensor value of the light emitted from the light source unit can be obtained with a high degree of precision. More specifically, a sensor value can be obtained after recognizing the color component of the light corresponding to the sensor value. As a result, high-precision processing based on the obtained sensor value can be executed. More specifically, values relating to the emission color and emission brightness of the light source unit can be determined with a high degree of precision.
A second embodiment of the present invention will now be described. In the first embodiment (
Detection Period Setting Method
A specific example of a method for setting the detection period will now be described using
The detection timing control unit 103 obtains the delay information and the light source control signal. In
The detection timing control unit 103 generates the sensor detection control signal on the basis of the delay information and the light source control signal. A reference numeral 507 in
The sensor detection control signal 507 in
Hence, in this embodiment, the detection timing control unit 103 sets the sensor detection control signal 508 shown in
More specifically, the detection timing control unit 103 calculates the time U corresponding to the phase using formulae 4 and 5 shown below, and generates the sensor detection control signal in accordance with the time U. In formulae 4 and 5, “T” denotes the length of the period in which the light source control signal 501=“High”, the length of the period of cyan light emission 502, the length of the period of red light emission 503, and so on. “S” denotes the length of the detection period. “J” denotes the length of the control period.
When T>V and (T+S)<J, U=at least (V+T−J) and not more than (V−S) (formula 4)
When T≤V, U=0 (formula 5)
Effects
According to this embodiment, as described above, a period in which only light of the target component is emitted from the light source unit can be set more reliably as the detection period. As a result, the effects described in the first embodiment can be obtained more reliably.
A third embodiment of the present invention will now be described. In the first and second embodiments, examples in which the light-emitting apparatus includes a single light source unit were described. In this embodiment, an example in which the light-emitting apparatus includes a plurality of light source units will be described. Note that points (configurations, processing, and so on) differing from the first embodiment will be described in detail below, while description of points that are identical to the first embodiment will be omitted.
Configuration of Light-Emitting Apparatus
An example configuration of the light-emitting apparatus according to this embodiment will now be described.
The periods of the plurality of light emission operations (cyan light emission and red light emission) are determined in accordance with the light source control signal (the lighting instruction). It may therefore be impossible to create a period in which a detection period can be set from the light source control signal. A period in which a detection period can be set is a period in which the brightness sensor 104 can detect a desired brightness (the brightness of light of a target component, emitted from a single light source unit) with a high degree of precision.
In the first and second embodiments, the single light source unit 101 is used. Hence, when the brightness sensor 104 detects the brightness of the light emitted from the light source unit 101, light emitted from another light source unit does not leak into the brightness sensor 104. In the first and second embodiments, therefore, the period in which a detection period can be set corresponds to the period in which only light of the target component is emitted from the light source unit 101, or the like.
In this embodiment, on the other hand, the three light source units 300A to 300C are used. Hence, when the brightness sensor 104 detects the brightness of light emitted from a target light source unit among the light source units 300A to 300C, light emitted from a light source unit on the periphery of the target light source unit may leak into the brightness sensor 104. This light leakage leads to a reduction in the detection precision of the brightness sensor 104. In this embodiment, therefore, the period in which a detection period can be set corresponds to a period in which only light of the target component is emitted from the target light source unit and the light source units on the periphery of the target light source unit are extinguished, or the like. For example, the period in which a detection period can be set corresponds to a period in which only light of the target component is emitted from the target light source unit and all of the light source units other than the target light source unit are extinguished. The light source units on the periphery of the target light source unit are light source units positioned at distances not exceeding a threshold from the target light source unit, for example. Alternatively, an adjacent light source unit to the target light source unit may be used alone as the light source unit on the periphery of the target light source unit.
The control unit 301 generates the light source control signal such that a period in which a detection period can be set is created, and outputs the light source control signal to the light source units. Generating the light source control signal may also be referred to as “executing the lighting instruction”. Further, the control unit 301 has similar functions (setting a detection period; generating and outputting the sensor detection control signal) to the detection timing control unit 103 of the first embodiment. In this embodiment, the control unit 301 corrects the light source control signal and generates the sensor detection control signal on the basis of the light source control signal and the delay information. The control unit 301 then outputs the corrected light source control signal and the sensor detection control signal. The light source control signal and the sensor detection control signal may be generated by separate function units.
In this embodiment, the control unit 301 executes the processing described above on each of the three light source units 300A to 300C. As a result, three light source control signals corresponding respectively to the three light source units 300A to 300C are generated, and three sensor detection control signals (detection periods) corresponding respectively to the three light source units 300A to 300C are generated.
The brightness sensor 104 and the color variation determination unit 107 execute the processing described in the first embodiment on each of the three light source units 300A to 300C. For example, with respect to each of the three light source units 300A to 300C, the color variation determination unit 107 obtains, from the brightness sensor 104, a detection value corresponding to the brightness detected by the brightness sensor 104 during the detection period corresponding to the relevant light source unit as a sensor value corresponding to the relevant light source unit.
Note that the delay information, the reference sensor value, and the color relationship information may be, but do not have to be, constituted by information (a value) that is shared by the three light source units 300A to 300C. Further, the light-emitting apparatus may include a plurality of brightness sensors. Correspondence relationships between the light source units and the brightness sensors may be determined in advance, and the brightness of the light emitted from a light source unit may be detected by the brightness sensor corresponding to the relevant light source unit.
Emission Period and Detection Period Setting Method
A specific example of a method for setting an emission period and a detection period will now be described using
As described above, the control unit 301 obtains the delay information and the light source control signal, and then corrects the light source control signal and generates the sensor detection control signal on the basis of the delay information and the light source control signal. A reference numeral 701 in
In the example shown in
In the example shown in
Hence, in this embodiment, as shown in
As shown in
In the example shown in
In the example shown in
Therefore, as shown in
Effects
According to this embodiment, as described above, for each of the plurality of light source units, a period in which the light source units on the periphery of the relevant light source unit are extinguished is set as the detection period corresponding to the relevant light source unit. Then, for each of the plurality of light source units, a sensor value corresponding to the brightness detected by the brightness sensor during the detection period corresponding to the relevant light source unit is obtained from the brightness sensor as the sensor value corresponding to the relevant light source unit. In so doing, when a plurality of light source units are used, the sensor value of the light emitted from each light source unit can be obtained with a high degree of precision, and accordingly, high-precision processing based on the obtained sensor value can be executed. More specifically, a sensor value in which effects from the other light beams are reduced can be obtained as the sensor value of the light emitted from the light source unit.
A fourth embodiment of the present invention will be described below. In this embodiment, an example in which the light-emitting apparatus is a display apparatus will be described. The display apparatus according to this embodiment includes a display unit that displays images by transmitting light emitted from a light source unit on the basis of display image data. The display apparatus is a liquid crystal display apparatus, a micro electro mechanical system (MEMS) shutter type display apparatus, or the like, for example. More specifically, the display apparatus is an advertisement display apparatus, a sign display apparatus, a projection apparatus (a projector), a PC, a PDA, a tablet terminal, a mobile telephone terminal, a television apparatus, an imaging apparatus, a digital photo frame, a game apparatus, a household electric appliance, an in-vehicle apparatus, or the like. Note that points (configurations, processing, and so on) differing from the first embodiment will be described in detail below, while description of points that are identical to the first embodiment will be omitted.
Configuration of Display Apparatus
An example configuration of the display apparatus according to this embodiment will now be described.
The color correction unit 801 generates display image data by correcting input image data on the basis of the sensor value obtained by the color variation determination unit 107 from the brightness sensor 104, taking into consideration the emission color of the light source unit 101. The input image data are image data input into the display apparatus, image data recorded in a storage unit, not shown in the figures, provided in the display apparatus, or the like. In this embodiment, the color correction unit 801 obtains the color variation value from the color variation determination unit 107, and generates the display image data by correcting the input image data on the basis of the color variation value. The color correction unit 801 then outputs the display image data to the display unit 802.
The display unit 802 displays an image on a screen by transmitting the light emitted from the light source unit 101 on the basis of the display image data. The display unit 802 is a liquid crystal panel, a MEMS shutter type display panel, or the like, for example.
Input Image Data Correction Method
A specific example of a method for correcting the input image data will now be described. There are no particular limitations on the format of the input image data, but here, an example of a case in which respective pixel values of the input image data correspond to RGB values (an R value, a G value, a B value)=(Ri, Gi, Bi) will be described.
Step 2-1
In step 2-1, the color correction unit 801 transforms the respective RGB values (Ri, Gi, Bi) into XYZ tristimulus values (Xpi, Ypi, Zpi). In this embodiment, the color correction unit 801 transforms the RGB values (Ri. Gi. Bi) of the input image data into XYZ tristimulus values (Xpi, Ypi, Zpi) using formula 6, shown below. Elements aX, aY, aZ, bX, bY, bZ, cX, cY, cZ on a transformation matrix of formula 6 are determined in advance on the basis of a measured value of the light emitted from the screen.
Step 2-2
In step 2-2, the color correction unit 801 divides the XYZ tristimulus values (Xpi, Ypi, Zpi) obtained in step 2-1 respectively by the color variation values (DX, DY, DZ). In this embodiment, the XYZ tristimulus values after being divided by the color variation values (DX, DY, DZ) will be referred to as “XYZ tristimulus values (Xoi, Yoi, Zoi)”. More specifically, as shown in formula 7, the color correction unit 801 calculates the X stimulus value Xoi by dividing the X stimulus value Xpi by the X variation value DX. As shown in formula 8, the color correction unit 801 calculates the Y stimulus value Yoi by dividing the Y stimulus value Ypi by the Y variation value DY. Further, as shown in formula 9, the color correction unit 801 calculates the Z stimulus value Zoi by dividing the Z stimulus value Zpi by the Z variation value DZ.
Xoi=Xpi/DX (formula 7)
Yoi=Ypi/DY (formula 8)
Zoi=Zpi/DZ (formula 9)
Step 2-3
In step 2-3, the color correction unit 801 transforms the XYZ tristimulus values (Xoi, Yoi, Zoi) calculated in step 2-2 respectively back into RGB values (Ro, Go, Bo) serving as the pixel values of the display image data. In this embodiment, the color correction unit 801 transforms the XYZ tristimulus values (Xoi, Yoi, Zoi) back into the RGB values (Ro, Go. Bo) using formula 10, shown below. The transformation matrix of formula 10 is an inverse matrix of the transformation matrix of formula 6.
Effects
According to this embodiment, as described above, display image data are generated by correcting input image data on the basis of a sensor value obtained with a high degree of precision, whereupon an image based on the display image data is displayed. As a result, unintended variation in the display color (the color of the screen), the display brightness (the brightness of the screen), and so on can be suppressed.
Note that the respective function units of the first to fourth embodiments may be, but do not have to be, constituted by individual hardware. The functions of two or more function units may be realized using shared hardware. Each of the plurality of functions of a single function unit may be realized by individual hardware. Further, two or more functions of a single function unit may be realized by shared hardware. Furthermore, the respective function units may be, but do not have to be, realized by hardware. For example, the apparatus may include a processor and a memory storing a control program, and the functions of at least some of the function units of the apparatus may be realized by having the processor read the control program from the memory and execute the program.
Note that the first to fourth embodiments are merely examples, and configurations obtained by appropriately amending or modifying the configurations of the first to fourth embodiments within the scope of the spirit of the present invention are also included in the present invention. Configurations obtained by appropriately combining the configurations of the first to fourth embodiments are likewise included in the present invention.
Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2017-117563, filed on Jun. 15, 2017, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-117563 | Jun 2017 | JP | national |
