JP5403512B2 - Light source brightness determination method and light source light emission method of display device - Google Patents

Description

The present invention relates to a light source brightness determination method and a light source light emission method for a display device in accordance with the visual perception of a target person such as an elderly person or a color weak person.

A light source for display may be provided on a remote control (remote operation device) or an operation panel installed in a system bath, a system kitchen, a vanity, or the like.
Moreover, the technique described in patent documents 1-4 is known as a technique which changes a display according to the aged person's or a visually impaired person's visual sensation.
In addition, the color deficient is also called a color blind person.

  Patent Document 1 discloses a screen display method for displaying an operation screen in a color tone assigned to a mode setting button selected from among mode setting buttons colored in different color tones. Therefore, the color of the operation screen changes according to the mode setting button operation.

The technique disclosed in Patent Document 2 calculates two types of color differences specific to color blind persons, refers to psychological scale values related to color recognition of healthy color blind persons from a color recognition characteristic database, and uses three types of color differences and psychological scales. A color that satisfies a certain criterion regarding the value is searched, and a color that cannot be identified by a color blind person is replaced with the searched color. Therefore, the color designed for the color blind person will change.
Note that Patent Document 2 describes that the luminance axis and the θ-axis are nonlinearly expanded / contracted, but does not describe how much the luminance axis is specifically expanded / contracted.

Patent Document 3 discloses an image display system having an image display device attached to a head or a face. This image display system detects an area of a color that is difficult for color blind persons to detect, detects an edge area of this area, adds a white line to the edge area in a superimposed manner, and displays a green area in blue To do. Therefore, the color and design designed for the normal person will change.
Patent Document 3 describes changing the display luminance of an image to a luminance value corresponding to the rotation direction and the rotation amount of the luminance change dial. Accordingly, the color blind person needs to perform an operation of adjusting the display brightness of the image, and there is no specific description of how much the display brightness of the image is changed according to the visual perception of the color blind person.

Patent Document 4 discloses an image display device that controls screen display in accordance with the state of eyes of a computer user. This image display device generates display control information including color and luminance conversion rules based on user status information such as presence / absence of presbyopia and color vision abnormality, and displays the display control information using the display control information. In the case of a user with color blindness, a color conversion rule for converting a specific color to another color, such as changing red or green to another color, is extracted. Therefore, the color of the screen display changes.
In addition, although patent document 4 describes converting luminance, it does not describe how much luminance is specifically converted.

Japanese Patent Application Laid-Open No. 2004-77828 JP 2007-293932 A JP 2007-122340 A JP 2007-010924 A

Colors have their own meanings such as red being hot and blue being cold. Therefore, changing the color as in the prior art results in the meaning of the color itself being lost, leading to a decrease in the ease of use of the product using the color. Even when creating a manual for a product, if the color displayed on the product changes, it becomes impossible to make an explanation using the color.
In addition, in order to extract a color boundary that is difficult for a color blind person to recognize, as in the techniques described in Patent Documents 1 and 3, image processing for extraction is required. Depending on the resolution of the display device or the like, the boundary portion may not be emphasized for a fine portion, or it may be difficult to see the reverse due to the enhancement.
On the other hand, there is no specific technique in the prior art that changes the display brightness to such an extent that it is easy for an elderly person or a color-weak person to visually recognize.

  In view of the above, an object of the present invention is to make it easy for a subject such as an elderly person or a color-weak person to visually recognize a display on a display device using a light source without changing the color.

In order to achieve the above object, the present invention provides a display that determines the brightness of the light source in accordance with the visual perception of the subject with reference to the standard brightness set for the standard user for the light source of the display device. A light source brightness determination method for an apparatus,
(A) The wavelength of light is λ, the spectral radiant intensity of the light source as a function of the wavelength λ is I (λ), and the spectral luminous efficiency of the subject as a function of the wavelength λ is V _o (λ ), a spectral luminous efficiency and has been standardized as a function of the wavelength lambda V (lambda), the luminous efficacy at a wavelength at which the spectral luminous efficiency V to the standard (lambda) is maximum k _m, the The visual effect efficiency at the wavelength at which the spectral luminous efficiency V _o (λ) of the subject is the maximum is _{km_o} , the wavelength on the short wavelength side of the visible radiation is λ _S , and the wavelength on the long wavelength side of the visible radiation is λ _L When the standard photosensitivity
And the visual sensitivity of the subject
Obtaining a value corresponding to the ratio of
(B) Based on the value obtained in the step (A), the brightness changed according to the ratio I _Lu / I _{Lu_o} of the I _{Lu to} the I _{Lu_o} with the standard brightness as a reference brightness of the light source And a step of determining as a feature.

That is, the present invention introduces a novel concept of a ratio between the standard visual sensitivity I _Lu and the subject's visual sensitivity I _{Lu_o} . Each photosensitivity can be said to be a psychophysical quantity representing the brightness felt by the standard user and the subject. According to the step (B), the brightness of the light source is changed according to the ratio I _Lu / I _{Lu_o} of the standard visual sensitivity I _{Lu to} the visual sensitivity I _{Lu_o} of the subject with the standard brightness as a reference. To be determined. The ratio I _Lu / I _{Lu_o} can be said to be the ratio between the psychophysical quantity of the standard user and the psychophysical quantity of the target person, and is the ratio that represents the difference in how the standard user feels the brightness of the target person. it can.
As described above, the brightness of the determined light source is close to the brightness that the standard user feels when viewing the display with the light source with the standard brightness when the subject views the display with the light source. Therefore, even if the color does not change, a subject such as an elderly person or a color weak person can easily see the display by the light source.

Even an elderly person or a color-weak person can recognize an object even if the color does not change if there is a difference in brightness between the object such as a character and the background. Therefore, by determining the brightness of the light source by the above-described method, the elderly person and the color-weak person can sufficiently visually recognize the display by the light source.
As described above, it is easy to realize a color universal design in consideration of color vision characteristics of a wide range of users such as elderly people and color-weak people.

By the way, the amount representing brightness according to the present invention includes luminous intensity, luminance, luminous flux, illuminance, and the like.
The ratio between the standard visual sensitivity I _Lu and the subject's visual sensitivity I _{Lu_o} includes both I _{Lu_o} / I _Lu and I _Lu / I _{Lu_o} .
The value representing the ratio of I _Lu and I _{Lu_o} is not only a value obtained by strict integration of the above formulas (1) and (2), but also the above formulas (1) and (2) are replaced with the sum of a sequence of numbers. Approximate values obtained in this way, values obtained by adding / subtracting / dividing predetermined values to / from these values, and the like are also included. In step (A), it is not necessary to obtain I _Lu itself or I _{Lu_o} itself, and a value representing the ratio between I _Lu and I _{Lu_o} may be finally obtained.
The brightness changed according to the ratio I _Lu / I _{Lu_o} with _respect to the standard brightness is the brightness expressed by an amount that is strictly obtained by multiplying the amount representing the standard brightness by the ratio I _Lu / I _{Lu_o.} In addition, the brightness closest to the brightness represented by the strictly determined amount among the brightness levels in a plurality of stages is included.

Further, the light source has n (n is an integer of 1 or more) peak wavelengths λ _pi (i is an integer from 1 to n), and the full width at half maximum corresponding to each peak wavelength λ _pi is λ _di . Using a light source,
In step (A), the standard deviation σ _i corresponding to each peak wavelength λ _pi is calculated.
And the spectral radiant intensity I (λ) is defined as I _i , which is a correction coefficient for the radiant intensity corresponding to each peak wavelength λ _pi.
And using the determined spectral radiant intensity I (λ), a value corresponding to the ratio between the I _Lu and the I _{Lu_o} may be obtained.
Here, the peak wavelength λ _pi refers to a wavelength at which the spectral radiation intensity I (λ) is a vertex. In the case of an ideal monochromatic light source, the peak wavelength _p is a single wavelength that maximizes the spectral radiation intensity I (λ).

Furthermore, the present invention is a light source emission method of a display device that emits the light source with the brightness determined by the above-described light source brightness determination method,
The display device is provided with light source brightness variable means for changing the brightness according to the input to emit the light source,
By performing input corresponding to the brightness determined in step (B) to the light source brightness variable means, the brightness of the light source that emits light at the standard brightness is determined in step (B). It is characterized by changing to the brightness that was made.
Here, the light source brightness varying means includes means for changing the width of the voltage pulse supplied to the light source, means for changing the amount of current supplied to the light source, means for changing the voltage supplied to the light source, and the like.

Furthermore, the light source emission method of the display device of the present invention selects a light source having a brightness closest to the brightness determined by the above-described light source brightness determination method from a plurality of light sources, and the selected light source is displayed on the display. It is characterized by being mounted on a device and emitting light .

According to the first aspect of the present invention, there is provided a light source brightness determination method capable of facilitating visual recognition of a display on a display device using a light source without changing a color for a subject such as an elderly person or a color weak person. Can do.
In the invention according to claim 2, even if the spectral radiant intensity of the light source is not known, the spectral radiant intensity of the light source is estimated from the peak wavelength and full width at half maximum of the light source to match the visual perception of the subject such as an elderly person or a color weak person. The brightness of the light source can be determined.
According to the third aspect of the present invention, there is provided a light source light emitting method capable of causing the light source of the display device to emit light with brightness according to the visual perception of a subject such as an elderly person or a color weak person without changing the light source. it can.
In the invention according to claim 4, the light source emission capable of causing the light source of the display device to emit light with brightness according to the visual perception of a subject such as an elderly person or a color weak person without providing a circuit for changing the brightness of the light source. A method can be provided .

It is a figure which illustrates the external appearance of the display apparatus 2 which concerns on 1st embodiment. 2 is a block diagram illustrating an outline of an electric circuit of a remote control system 1 having a display device 2. FIG. It is a figure for demonstrating the example which changes the brightness of the light source 34 by pulse width modulation control. It is a figure which shows the kind and name of a person's color vision characteristic. It is a figure which illustrates the structure of brightness perception efficiency database DB1. It is a block diagram which illustrates the outline of the structure of the computer 80 used for the light source brightness determination method. 4 is a flowchart illustrating a process performed by the display device 2. It is a figure which illustrates the spectral radiation intensity | strength I ((lambda)) of LED. It is a diagram illustrating the elderly and secondary color vision's spectral luminous efficiency V _o (λ). Elderly and first die two color vision's spectral luminous efficiency V _elderly (λ), is a diagram illustrating a coefficient of determination R ² for the next number polynomial in the case of polynomial fitting _V protan (λ). It is a figure which illustrates the difference in the brightness perception efficiency BPE _elderly of an elderly person by the difference in the full width at half maximum of a light emitting diode. It is a figure which illustrates the difference in the brightness perception efficiency BPE _protan of a 1 type _{| mold bicolor} person by the difference in the full width at half maximum of a light emitting diode. It is a flowchart which illustrates the light source brightness determination process which the computer 80 performs. It is a flowchart which illustrates the spectral radiant intensity distribution determination process which the computer 80 performs. It is a flowchart which illustrates the process which the display apparatus which concerns on 2nd embodiment performs. It is a block diagram which illustrates the outline of the electric circuit of the remote control system 101 which concerns on 3rd embodiment. It is a figure which illustrates typically the light source light emission method of the display apparatus which concerns on 3rd embodiment. It is a figure which illustrates the external appearance of the display apparatus 202 which concerns on 4th embodiment. It is a block diagram which illustrates the outline of the electric circuit of the remote control system 201 which concerns on 4th embodiment.

Hereinafter, embodiments of the present invention will be described in the following order.
(1) Outline of display device according to first embodiment:
(2) Outline of light source brightness determination method and light source light emission method of display device:
(3) Description of computer used for light source brightness determination method:
(4) Explanation of processing of display device:
(5) Method for determining the spectral radiation intensity I (λ) of the light source:
(6) Description of spectral luminous efficiency V _o (λ) for elderly and dichromates:
(7) Description of brightness perception efficiency BPE:
(8) Description of light source brightness determination method using brightness perception efficiency BPE:
(9) Description of light source brightness determination method by light source brightness determination program:
(10) Explanation of effects of light source brightness determination method and light source light emission method:
(11) Various modifications:

(1) Outline of display device according to first embodiment:
As shown in FIGS. 1 and 2, the remote control system 1 uses the remote control device 2 (hereinafter referred to as “remote control device”) 2 serving as a display device of the present invention to turn on and off the illuminations 44 to 46 and change the brightness of the spot illuminations 45 and 46. Remote control is possible. Various operation buttons 23 a to 23 e and 24 a to 24 c and various LEDs (Light Emitting Diodes) 34 are provided on the operation panel 21 provided on the front surface of the remote control device 2. Here, the illumination operation buttons 23 a to 23 c are push button switches for turning on and off the illuminations 44 to 46. The illumination operation buttons 23d and 23e are push button switches for changing the brightness of the spot illuminations 45 and 46 in stages. The LED 34a is a point light source for indicating which spot illuminations 45 and 46 are lit. The LED 34b is a point light source for indicating the brightness of the lit spot illumination. These LEDs 34a and 34b have a narrow display area with a viewing angle of less than 2 ° when viewed from a position when operating the remote control device 2 (for example, a distance of 50 cm).
The remote control device 2 of the present embodiment includes mode switching buttons 24a to 24c for changing the brightness of the LED 34 in accordance with the visual sensation of the elderly and the color deficient. The mode switching buttons 24a to 24c are respectively push button switches for selecting and operating the normal mode, the elderly person mode, and the one-type two-color person mode.

As shown in FIG. 2, in the remote control device 2, the operation unit 20 and the light source brightness varying means 31 are connected to the control unit 10.
The control unit 10 includes a CPU (Central Processing Unit) 11, a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13, a nonvolatile semiconductor memory 14, an I / O (input / output) circuit 15, etc. Is a connected microcomputer (microcomputer). The ROM 12 stores a program for controlling on / off of the illuminations 44 to 46 and changing the brightness of the spot illuminations 45 and 46. The nonvolatile memory 14 stores pulse width values 14a to 14c corresponding to the pulse width for changing the brightness of the LED 34 by PWM (Pulse Width Modulation) control. A pulse width command value for commanding the pulse width of PWM control is output from the I / O circuit 15 to the pulse width control circuit 32 of the light source brightness varying means 31. Further, an illumination control signal for controlling on / off of the illuminations 44 to 46 and the brightness change of the spot illuminations 45 and 46 is output from the I / O circuit 15 to the illumination drive circuits 41 to 43. The CPU 11 controls each part of the remote control device 2 based on a program recorded in the ROM 12.
The operation unit 20 is provided with the various operation buttons 23a to 23e and 24a to 24c described above.

The light source brightness varying means 31 includes a pulse width control circuit 32 and a light source driving circuit 33, and changes the brightness according to the input from the control unit 10 to cause the LED 34 to emit light.
The pulse width control circuit 32 receives a pulse width command value from the control unit 10 and generates a PWM signal having a pulse width corresponding to the pulse width command value. As the pulse width control circuit 32, a known circuit can be used. For example, a PWM signal can be generated based on the principle shown in FIG. Here, in the graph shown in FIG. 2, the horizontal axis represents time t, and the vertical axis represents the count value of the counter. The pulse width control circuit 32 shown in FIG. 2 counts the pulse synchronized with the clock with the counter, returns the counter to 0 when the counter value reaches the clear value, and outputs the PWM signal when the counter value returns to 0. The PWM signal is switched from ON to OFF when the counter value reaches the pulse width command value. The interval for returning the counter to 0 is set to such a short interval that the on / off state of the LED emission is not recognized by human eyes. In the case of the example shown in FIG. 2, the duty ratio of the PWM signal representing the ratio of the LED lighting time to the total time increases as the pulse width command value increases. Of course, the brightness of the LED 34 can be changed by PWM control even in a pulse width control circuit that generates a PWM signal that is turned on and off opposite to the PWM signal shown in FIG.

The light source drive circuit 33 inputs a PWM signal from the pulse width control circuit 32 and supplies a constant current having a pulse width synchronized with the PWM signal to the LED 34. A known circuit can be used as the light source driving circuit 33. For example, an output current having a voltage sufficient to light the LED 34 with a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), a constant current regulator, or the like is used as a PWM signal. Turn on and off according to.
The LEDs 34a and 34b emit light by inputting a pulsed current from the light source driving circuit 33. This current has a pulse width corresponding to the pulse width command value from the control unit 10. If the on / off cycle of LED light emission is so short that it cannot be seen by the human eye, the LED apparently has a light intensity proportional to the duty ratio.

  The illumination drive circuits 41 to 43 connected to the remote control device 2 receive the illumination control signal from the control unit 10 and drive (turn on / off) the illuminations 44 to 46 according to the illumination control signal, and brightness of the spot illuminations 45 and 46. To control.

By the way, the most basic functional requirement of an operation / display device using an LED is to easily recognize the lighting of the LED. In addition, as a device interface design, there is a demand for a design (color universal design) that takes into account the color vision characteristics of a wide range of users such as elderly people and color-impaired people. However, a method for quantitatively estimating the influence of the light emission wavelength characteristics (peak wavelength, emission spectrum spread, etc.) of the LED on the brightness perceived by the elderly and the color deficient has not been studied. For this reason, the hardware designer of the device did not know what kind of optical characteristics the LED would have if it was used for the product, making it easier for the elderly and the color-blind.
On the other hand, changing the color of the interface design loses the meaning of the color itself, leading to a decrease in usability of the product using the color.
Therefore, the remote control device 2 of the present embodiment is a device that makes it easy to visually recognize the LED 34 without changing the color.

(2) Outline of light source brightness determination method and light source light emission method of display device:
In order to determine the brightness of the LED 34 of the remote control device 2, as a first step (A), a value I _{Lu_o} corresponding to the ratio of the standard photosensitivity I _Lu and the photosensitivity I _{Lu_o} of the elderly or the color- _deficient / I want to find _Lu . This value I _{Lu_o} / I _Lu represents how many times the brightness felt by a standard user when an elderly person or a color-blind person sees a lighted LED. Hereinafter, the value I _{Lu_o} / I _Lu will be referred to as “brightness perception efficiency”.
As a second step (B) for determining the brightness of the LED 34, the brightness is determined based on the standard brightness set for the standard user based on the brightness perception efficiency I _{Lu — o} / I _Lu. The brightness changed according to the reciprocal I _Lu / I _{Lu_o} of the perceptual efficiency is determined as the brightness of the LED 34.

  When the LED 34 is caused to emit light, the brightness corresponding to the brightness determined in the second step (B) is input to the light source brightness varying means 31 so that the brightness of the LED 34 that emits light with standard brightness is obtained. Is changed to the brightness determined in the second step (B).

When the brightness of the LED 34 is changed by PWM control, the duty ratio of the PWM signal set in accordance with the standard user may be set to the inverse of the brightness perception efficiency.
FIG. 3 shows an example in which the brightness of a certain blue LED 34 is changed by PWM control. Here, BPE indicates brightness perception efficiency I _{Lu — o} / I _Lu . In the example of FIG. 3, it is shown that the duty ratio of the PWM signal is 20.0% in the normal mode for the young tri-colored person. Further, it is shown that the brightness perception efficiency BPE _{elderly of the elderly} is 0.22, and the brightness perception efficiency BPE _protan of the one-type dichroic person is 1.51.

When the target person is an elderly person, since BPE _elderly = 0.22, the brightness of the LED 34 is determined to be 1 / 0.22 times the standard brightness. Therefore, if the duty ratio of the PWM signal is 20.0 × (1 / 0.22) = 90.9%, when the elderly person sees the LED in the lit state, the brightness is the same as that of the standard user. You will feel it.
Further, when the target person is a one-type two-color person, since BPE _protan = 1.51, the brightness of the LED 34 is determined to be 1 / 1.51 times the standard brightness. Therefore, if the duty ratio of the PWM signal is set to 20.0 × (1 / 1.51) = 13.2%, when the one-type two-colored person sees the LED in the lit state, it is equivalent to the standard user You will feel the brightness.
Note that the brightness perception efficiency of the subject varies depending on the spectral luminous characteristics of the subject and the spectral radiant intensity distribution of the light source. Therefore, it is necessary to determine the brightness of the light source in accordance with the spectral visual characteristics of the subject and the spectral radiant intensity distribution of the light source.

  Many humans recognize colors with three types of photoreceptor cells: L cone, M cone, and S cone. A person who does not have one or more cones among these cones, or a person whose cone functions are insufficient, is called a color blind person. FIG. 4 shows the types and names of human color vision characteristics. As shown in FIG. 4, a person who does not have only an L cone that detects light having a wavelength close to red has a one-type two-color sense, a person who has an insufficient function of the L cone has a one-type three-color sense, and has a wavelength close to green. A person who does not have only an M cone that detects M-type two-color vision, a person who has insufficient M-cone function has a two-type three-color sense, and a person who does not have an S-cone that detects light of a wavelength close to blue. People with insufficient color vision and S cone function are called three-type three-color vision. Japanese are 5% male and 0.2% female are weak.

  From the above, it is conceivable to finely determine the brightness of the light source for the color weak according to the type of the color weak. In the present embodiment, based on the spectral luminous efficiency data shown in FIG. 9, the subjects who determine the brightness of the light source are the elderly and the one-type dichroic person. Then, the brightness perception efficiency database DB1 shown in FIG. 5 is constructed for the computer 80 as shown in FIG. In this brightness perception efficiency database DB1, brightness perception efficiency BPE is stored for each light source for the elderly and the one-type dichroic person.

(3) Description of computer used for light source brightness determination method:
In the computer 80 shown in FIG. 6, a CPU 81, ROM 82, RAM 83, nonvolatile memory 84, input device 85, output device 86, recording device 87, I / F (interface) 88, and the like are connected to an internal bus. As the input device 85, an operation input device such as a keyboard and a mouse (pointing device) can be used. As the output device 86, an image output device such as a display can be used. The recording device 87 can read / write data from / to a computer-readable recording medium. The I / F 88 can transmit / receive data to / from an external device.

As the nonvolatile memory 84, a hard disk, a nonvolatile semiconductor memory, or the like can be used. The non-volatile memory 84 has a program P1 used for determining the brightness of the light source, a standard spectral luminous efficiency V (λ), the spectral luminous efficiency V _o (λ) of the subject, and the maximum luminous efficacy k. _m , the subject's maximum luminous effect degree k _{m_o} , the spectral radiation intensity I (λ), the standard luminous sensitivity I _Lu , the subject's luminous sensitivity I _{Lu_o} , brightness perception efficiency BPE, and the like are stored. .
The user of the computer 80 can calculate the standard visual sensitivity I _Lu using the maximum luminous efficacy of k _m a spectral radiant intensity I (lambda) and the standard spectral luminous efficiency V (λ). The subject's luminous sensitivity I _{Lu_o} can be calculated using the spectral radiation intensity I (λ), the subject's spectral luminous efficiency V _o (λ), and the subject's maximum luminous efficacy k _{km_o.} . Then, the brightness of the light source of the display device can be determined using the visual sensitivity I (λ) and I _{Lu_o} .

  When the brightness for the target person is determined, the pulse width value 14a with the LED 34 as the standard user brightness and the pulse width values 14b and 14c with the LED 34 as the target brightness are written into the nonvolatile memory 14. . In the example shown in FIG. 3, the pulse width values 14a, 14b, and 14c for setting the duty ratio of the PWM signal to 20.0%, 90.9%, and 13.2%, respectively, are stored in the nonvolatile memory 14. .

(4) Explanation of processing of display device:
The control unit 10 of the remote control device 2 performs the process shown in FIG. 7, and causes the LED 34 to emit light with the brightness determined by the light source brightness determination method of the present embodiment. The processing shown in FIG. 7 is started when the mode switching buttons 24 a to 24 c are pressed, and is executed by the CPU 11 according to the program written in the ROM 12.
First, the control unit 10 determines which mode has been selected and operated (step S102; hereinafter, description of “step” is omitted).

When the mode switching button 24a is operated, the normal mode is selected, and a pulse width command value for a young tri-colored person is acquired in S104. When the pulse width values 14 a to 14 c stored in the nonvolatile memory 14 become the pulse width command value, the pulse width value 14 a for the young tri-colored person may be read from the nonvolatile memory 14. Of course, when the pulse width values 14a to 14c are not directly the pulse width command value, the read pulse width value 14a may be converted into the pulse width command value.
When the mode switching button 24b is operated, the elderly person mode is selected, and a pulse width command value for elderly persons is acquired in S106. In S106, the pulse width value 14b for elderly people is read from the nonvolatile memory 14, and may be converted into a pulse width command value as necessary.
When the mode switching button 24c is operated, the one-type dichroic person mode is selected, and the pulse width command value for the one-type dichroic person is acquired in S108. In S108, the pulse width value 14c for the one-type two-color sensation person is read from the nonvolatile memory 14 and converted into a pulse width command value as necessary.

  After S104, S106, and S108, the control unit 10 outputs the acquired pulse width command value to the pulse width control circuit 32 (S110). Further, the control unit 10 controls on / off of the illuminations 44 to 46 and change of the brightness of the spot illuminations 45 and 46 according to the operation of the operation buttons 23a to 23e, and controls on / off of the LEDs 34a and 34b (S112). The pulse width control circuit 32 having received the pulse width command value generates a PWM signal having a pulse width corresponding to the pulse width command value. The light source drive circuit 33 turns on the LEDs 34a and 34b that are turned on at intervals corresponding to the PWM signals. As a result, the LEDs 34a and 34b that emit light with standard brightness are changed to the brightness determined for the elderly when the elderly mode is selected, and the LEDs 34a and 34b are turned on when the one-type two-color vision mode is selected. It is changed to the brightness determined for the type two-color vision person.

(5) Method for determining the spectral radiation intensity I (λ) of the light source:
The brightness of the LED is greatly affected by its spectral radiant intensity distribution. For this reason, in order to estimate the brightness of a single color LED felt by an individual, it is necessary to know the spectral radiant intensity distribution of each LED. However, it is rare for spectral radiant intensity data to be provided for commercial LEDs. The data provided for the optical properties of monochromatic LEDs are generally peak wavelength, dominant wavelength, full width at half maximum (FWHM), and luminous intensity. Therefore, the spectral radiant intensity distribution of the monochromatic LED is estimated from these data.

Since the spectral radiant intensity distribution of a single color LED is influenced by the probability density distribution of the energy gap of the LED element, it often takes a form close to a Gaussian distribution. Therefore, it is assumed that the spectral radiant intensity I (λ) of the monochromatic LED is a Gaussian function of Equation (5) with the peak wavelength λ _p (nm) and the full width at half maximum λ _d (nm) as parameters.
However, I (λ) in Expression (5) is a relative value that becomes 1 when the wavelength λ (nm) of light is the peak wavelength λ _p . When calculating the brightness perception efficiency BPE = I _Lu — _o / I _Lu , I (λ) is included in both the luminous sensitivities I _Lu and I _{Lu — o} , so I (λ) should be a relative value. Can do. In order to set the spectral radiant intensity I (λ) in units of W / sr · nm, the equation (5) may be multiplied by a correction coefficient I (W / sr) of the radiant intensity. In this case, the unit of the visual sensitivity I _Lu and I _{Lu_o} is cd.

The standard deviation σ (nm) of the Gaussian function is obtained from the full width at half maximum λ _d .
FIG. 8A shows the spectral radiant intensity distribution estimated for the full width at half maximum of 25 nm and 65 nm for a blue LED having a peak wavelength of 465 nm. However, the spectral radiation intensity at a wavelength of 465 nm is set to 1 (W / sr · nm).

When 98 types of commercially available visible light monochromatic LEDs (4 manufacturers, bullet type) were investigated, the peak wavelength was 430 to 700 nm, and the full width at half maximum was 12 to 100 nm.
Therefore, the brightness perceived by the subject is estimated for the range of peak wavelength and full width at half maximum shown in Table 1.

  Even in a non-monochromatic LED, an LED having different color LED chips as one light source has a spectral radiation intensity distribution having a peak wavelength for each color. For example, a white LED used for a backlight of a liquid crystal display or the like includes a red chip, a green chip, and a blue chip. Such a white LED has a spectral radiant intensity distribution having peak wavelengths at a red wavelength, a green wavelength, and a blue wavelength.

Therefore, consider a case where a light source having n (n is an integer of 1 or more) peak wavelengths λ _pi (i is an integer from 1 to n) is used for a display device. Assuming that the full width at half maximum corresponding to each peak wavelength λ _pi (nm) is λ _di (nm), the standard deviation σ _i (nm) corresponding to each peak wavelength λ _pi is the above-described equation (3), that is,
It becomes. _Assuming that the correction coefficient of the radiation intensity corresponding to each peak wavelength λ _pi is I _i (W / sr), the spectral radiation intensity I (λ) (W / sr · nm) is expressed by the above-described equation (4), that is,
It becomes. Therefore, the spectral radiant intensity I (λ) of the LED can be determined using the equation (4).
Of course, if n = 1, the above expression (5) is substantially obtained.

The determined spectral radiation intensity I (λ) can be used to obtain the brightness perception efficiency BPE corresponding to the ratio between the standard visual sensitivity I _Lu and the subject's visual sensitivity I _{Lu_o} .
FIG. 8B shows the spectral radiant intensity distribution estimated for the LEDs having peak wavelengths at 465 nm and 585 nm with a full width at half maximum of 30 nm. However, the spectral radiation intensity at both wavelengths of 465 nm and 585 nm is 1 (W / sr · nm). Of course, if there is a difference in intensity between the spectral radiation intensities at the peak wavelengths, the correction coefficient I _i may be set according to the intensity.

  According to the method for determining the spectral radiant intensity distribution described above, even if the spectral radiant intensity of the light source is not known, the spectral radiant intensity of the light source is estimated from the peak wavelength and full width at half maximum of the light source to match the visual perception of the subject. The brightness of the light source can be determined.

(6) Description of spectral luminous efficiency V _o (λ) for elderly and dichromates:
The perception of the brightness of the light source is greatly influenced by the individual spectral luminous efficiency V _o (λ).
FIG. 9 shows the spectral luminous efficiency V _{elderly of the elderly} , the spectral luminous efficiency V _{protan of} the type 1 dichroic person, the spectral luminous efficiency V _{deuteran of} the type 2 dichroic person, and the spectral luminous efficiency of the type 3 dichroic person. The case of photopic vision is illustrated for V _tritan and CIE standard spectral luminous efficiency V (λ) agreed in CIE (International Commission on Illumination). Here, the horizontal axis represents wavelength λ (nm), and the vertical axis represents spectral luminous efficiency. These spectral luminous efficiencies are suitable for use when evaluating brightness when viewing a display with a narrow viewing angle (less than 2 ° viewing angle). For example, many LEDs such as a cannonball type are point light sources having a viewing angle of less than 2 ° at a normal viewing position, and are suitable for evaluating brightness using the brightness perception efficiency BPE.
In the figure, "Elderly 70's", "Protanopes", "Deuteranopes", "Tritanopes", and "CIE V (λ)" are the elderly people in their 70s, type 1 dichromatic, type 2 dichromatic, 3 type dichroic person, CIE standard spectral luminous efficiency.
Spectral luminous efficiency of elderly people in their 70s is K. Sagawa and Y. Takahashi: Spectral luminous efficiency as a function of age, J. Opt. Soc. Am (A), 18 pp. 2659-2667 (2001) Spectral luminous efficiency reported in. This document also describes that the CIE standard spectral luminous efficiency best matches the spectral luminous efficiency of 25 years old. Therefore, a young tricolor person is a person who is 25 years old and whose spectral luminous efficiency is the CIE standard spectral luminous efficiency. In the present embodiment, this young tricolor person is the standard user.
The spectral luminous efficiency of the dichroic person uses the spectral luminous efficiency reported in the following documents (a) to (e).
(A) A. Stockman, NI MacLeod and NE Johnson: Spectral sensitivities of the human cones, J. Opt. Soc. Am (A), 10, pp. 2491-2521 (1993).
(B) VC Smith and J. Pokorny: Spectral sensitivity of the foveal cone photopigments between 400 and 500 nm, Vision Res., 15, pp. 161-171 (1975).
(C) Y. Hsia and CH Graham: Spectral luminosity curves for protanopic, deuteranopic, and normal subjects, in Proceedings of the National Academy of Sciences of USA, 43, pp. 1011-1019 (1957).
(D) G. Wyszecki and W. Stiles: Color Science 2nd Edition, John Wiley and sons (1982).
(E) WD Wright: The characteristics of tritanopia, ”J. Opt. Soc. Am., 42, pp. 509-521 (1952).

As shown in FIG. 9, the spectral luminous efficiency V _elderly of the elderly people in their 70s is the lowest in the wavelength region shorter than 550 nm, and the spectral luminous efficiency of the one-type dichroic person is longer in the wavelength region longer than 550 nm. V _protan is the lowest. This indicates that it is necessary to take into account the difference in the spectral luminous efficiency of individuals, particularly focusing on the decrease in sensitivity between the elderly and type 1 dichroic persons. Therefore, in the present embodiment, the brightness of the light source is determined with the elderly person and the one-type dichroic person as subjects.

In order to estimate the brightness of the light source perceived by the subject, the results of the existing study shown in FIG. 9 for the spectral luminous efficiency V _elderly , V _protan of the _elderly and the one-type dichroic person are expressed by equations (7), ( Fitting with the polynomial of 8).
FIG. 10 shows the coefficient of determination R ² with respect to the degree of the polynomial when the spectral luminous efficiency V _elderly (λ) and V _protan (λ) of the elderly person and the one-type dichroic person are _subjected to polynomial fitting. Here, the horizontal axis represents the order of the polynomial, and the vertical axis represents the coefficient of determination R ^2. In the figure, “Protanopia” and “Elderly 70yrs” indicate a type 1 dichroic person and an elderly person in their 70s, respectively.
In the case of the elderly, the coefficient of determination hardly increased even when the order was increased from the 9th order. In the case of a type 1 dichroic person, the coefficient of determination hardly increased even when the order was increased from the 7th order. Therefore, the spectral luminous efficiency V _elderly (λ) of the _elderly was fitted with a ninth-order polynomial, and the spectral luminous efficiency V _protan of the one-type dichroic person was fitted with a seventh-order polynomial.

Table 2 shows the approximation coefficient a _i for the elderly.
In the table, “*. * ... * E-**” is *. * ... * x10 ^-** means "*. * ... * E + ***" means *. * ... means * 10 ^** .
By applying the approximation coefficient a _i in Table 2 to the equation (7), the spectral luminous efficiency V _elderly (λ) of the elderly can be used to calculate the luminous sensitivity I _{Lu_elderly} of the elderly.

Table 3 shows the approximation coefficient a _i in the case of a one-type dichroic person.
By applying the approximation coefficient a _i in Table 3 to the equation (8), the spectral luminous efficiency V _elderly (λ) of the one-type dichroic person is used to calculate the visual sensitivity I _{Lu_protan} of the one-type dichroic person. Can do.

(7) Description of brightness perception efficiency BPE:
When the spectral radiant intensity of the light source that is a function of the wavelength lambda I (lambda) is determined, photopic maximum luminous effect degree defined as in CIE CIE standard spectral luminous efficiency V (lambda) of a standard in view k _m = 683 lm / W can be used to determine the standard visual sensitivity I _Lu . Here, the CIE standard spectral luminous efficiency V (λ) is the spectral luminous efficiency of a young tri-colored person. Maximum luminous effect of k _m are, CIE standard spectral luminous efficiency V (lambda) is the luminous effect of the radiation at the wavelength of maximum. In photopic vision, the CIE standard spectral luminous efficiency is maximized when the wavelength is 555 nm.
The standard photosensitivity I _Lu is the above-described formula (1), that is,
It becomes. Here, λ _S is the wavelength on the short wavelength side of visible radiation, and λ _L is the wavelength on the long wavelength side of visible radiation. Since the spectral radiant intensity I (λ) is multiplied by the spectral luminous efficiency V (λ) of the young tri-colored person, the standard visual sensitivity I _Lu is a psychophysical quantity representing the brightness felt by the young tri-colored person. be able to.

Further, when the spectral luminous efficiency V _o (λ) of the subject as a function of the wavelength λ and the spectral radiant intensity I (λ) of the light source are obtained, the spectral luminous efficiency V _o (λ) of the subject is obtained. The visual sensitivity I _{Lu_o} of the subject can be obtained using the visual effect degree _{km_o} at the maximum wavelength. Here, _{km_o} is _referred to as the maximum visual effect level of the subject. The visual sensitivity I _{Lu_o} of the _subject is the above-described formula (2), that is,
It becomes. Since the spectral radiation intensity I (λ) is multiplied by the subject's spectral luminous efficiency V _o (λ), the subject's visual sensitivity I _{Lu_o} is a psychophysical quantity representing the brightness perceived by the subject. it can.
Note that the photosensitivities I _Lu and I _{Lu_o} can be calculated by calculating an approximate value using the computer 80.

When the standard visual sensitivity I _Lu and the subject's visual sensitivity I _{Lu_o} are obtained, the brightness perception efficiency BPE = I _{Lu_o} / I _Lu can be obtained. From the expressions (1) and (2), the brightness perception efficiency BPE is
It becomes. The brightness perception efficiency BPE can be said to be the ratio of the subject's psychophysical quantity to the standard user's psychophysical quantity, and can be said to be the ratio representing the difference in how the subject's brightness is perceived by the standard user. The brightness perception efficiency BPE is determined by how many times the light intensity of a light source of a young tricolor person who has CIE standard spectral luminous efficiency V (λ) is viewed. In other words, it can be paraphrased as a dimming rate (magnification factor) that indicates whether you can experience the brightness you feel. Therefore, by using the brightness perception efficiency BPE, it is possible to quantitatively determine the brightness of the light source in accordance with the visual perception of the subject such as an elderly person or a one-type dichroic person.

The visible radiation range for calculating the brightness perception efficiency BPE can be, for example, the wavelength λ _S = 400 nm on the short wavelength side and the wavelength λ _L = 700 nm on the long wavelength side. Since the wavelength limit of visible radiation specified in JIS Z8113: 1998 (illumination terminology) is 360 to 400 nm on the short wavelength side and 760 to 830 nm on the long wavelength side, the wavelengths λ _S and λ _L are set to fall within these ranges. May be set.

By the way, in order to obtain the subject's visual sensitivity I _{Lu_o} , it is _necessary to obtain the subject's maximum visual effect degree _{km_o} .
Werner et al. Examined the age-related change of the absolute threshold in photopic vision for light with a wavelength of 560 nm, and the absolute threshold was 0.008A + 7.68410 with age (A is age, unit is log quanta · sec ⁻¹ · deg ^{− 2} ) (JS Werner, KA Schelble and ML Bieber: Age-related increases in photopic increment thresholds are not due to an elevation in intrinsic noise, Color Res. Appl., 26-S1 , pp. S48-S52 (2001)). This absolute threshold means a boundary value of whether or not light is visible, and the reciprocal of the absolute threshold corresponds to the sensitivity of the eye. Assuming that the young tricolored person is 25 years old and the elderly is 70 years old, the absolute threshold values of the young tricolored person and the elderly are 7.884 and 8.244 (log quanta · sec ⁻¹ · deg ^-2 ), respectively. This means that the sensitivity of the elderly to 560 nm light is reduced 0.437 times (= 10 ^{7.884 /10.244} ) ^compared to the young ^tricolor .
Moreover, according to JIS and CIE, the spectral luminous efficiency and CIE standard spectral luminous efficiency of elderly people with respect to 560 nm light are 0.999 and 0.995, respectively. Therefore, we determine the maximum luminous effect of the elderly and _{k m_e = 0.437 · (0.995 /} 0.999) k m = 0.435k m.

For type 1 dichromats, an experiment using a Goldmann-Weekers accelerometer reported that the absolute threshold of type 1 dichromats for white light is almost the same as that for tricolors (AE Krill and E Beutler: The red-light absolute threshold in heterozygote protan carriers; Possible genetic implications, Invest. Ophthalmol. Vis. Sci., 3, pp. 107-118 (1964).). Therefore, for the brightness perception efficiency equation defined by equation (9), a 7th order approximation polynomial representing the spectral luminous efficiency V _protan of a one-type dichroic person is used as V _o , and the standard defined by CIE The spectral radiant intensity distribution of light A (white light) was used as I (λ), BPE = 1 was assumed, and _{km_o} was calculated with λ _S = 400 nm and λ _L = 700 nm. As a result, it became _k m_o = 1.380k _m.
Thus, to determine the maximum luminous efficacy of the first die two color vision person and _k m_p = 1.380k _m.

λ _S = 400 nm and λ _L = 700 nm, the brightness perception efficiency of the elderly
Substituting into the maximum luminous effect degree k _{m_e} of the elderly person and the expressions (5) and (7), the brightness perception efficiency of the elderly person with respect to the peak wavelength λ _p and the full width at half maximum λ _d of the monochromatic LED can be calculated. . FIG. 11 shows the results calculated in this way, and shows the difference in the brightness perception efficiency BPE _elderly of the _elderly due to the difference in the full width at half maximum λ _d of the monochromatic LED.

As shown in FIG. 11, in the case of an elderly person, the brightness perception efficiency BPE _elderly was the lowest at 0.212 when the peak wavelength was 475 nm and the full width at half maximum was 15 nm. BPE _elderly = 0.212 means when a young tri-colored person sees the same LED whose brightness is reduced to about 21% when the elderly person sees a monochromatic LED with a peak wavelength of 475 nm and a full width at half maximum of 15 nm. It is equivalent to the brightness you feel. If the monochromatic LED has a full width at half maximum of 100 nm even if the peak wavelength is 475 nm, the brightness perception efficiency is 0.337, and the LED brightness reduction felt by the elderly is reduced compared to the case of the full width at half maximum of 15 nm.
In the peak wavelength range of 530 to 610 nm, even if the full width at half maximum was changed in the range of 15 to 100 nm, the change in brightness perception efficiency was 0.03 or less. This indicates that, in the peak wavelength range of 530 to 610 nm, if the peak wavelength is the same, even if the full width at half maximum is different, the brightness of the LED felt by the elderly hardly changes.
On the other hand, at a peak wavelength of 610 nm or more, an LED with a narrow full width at half maximum has a higher brightness perception efficiency than an LED with a wide full width at half maximum, so it is expected that an LED with a narrow full width at half maximum will feel brighter.

In addition, brightness perception efficiency of type 1 dichromatic
Substituting into the maximum luminous efficacy k _{m_p of} the type 1 _{dichroic person} and the equations (5) and (8), the brightness perception efficiency of the type 1 dichroic person with respect to the peak wavelength λ _p and the full width at half maximum λ _d Can be calculated. FIG. 12 shows the results calculated in this way, and shows the difference in the brightness perception efficiency BPE _protan of the one-type dichroic person due to the difference in the full width at half maximum λ _d of the monochromatic LED.

As shown in FIG. 12, in the case of the one-type two-color vision, the brightness perception efficiency BPE _protan was lowest at 0.053 when the peak wavelength was 700 nm and the full width at half maximum was 15 nm. BPE _protan = 0.053 means that a _{young tri} -colored person can see the same LED whose brightness is reduced to about 5% when a single-type two-colored person sees a monochromatic LED with a peak wavelength of 700 nm and a full width at half maximum of 15 nm. It means that it is equivalent to the brightness you feel when you see it.
As can be seen from FIG. 12, when the peak wavelength is longer than 535 nm, if the full width at half maximum is widened, the decrease in the brightness perception efficiency of the one-type dichroic person can be suppressed. For example, in the case of an LED with a peak wavelength of 635 nm, the brightness perception efficiency is 0.229 when the full width at half maximum is 15 nm, but the brightness perception efficiency is 0.663 when the full width at half maximum is 100 nm. On the other hand, when the peak wavelength is shorter than 535 nm, the brightness perception efficiency of the type 1 dichroic person is 1 or more regardless of the full width at half maximum. The absolute threshold of a type 1 dichroic person with respect to white light is almost the same as that of a 3 color conscious person. In the case of a type 1 dichroic person, the sensitivity at the short wavelength increases as the sensitivity on the long wavelength side decreases. It is expected that Therefore, there is a possibility that the one-type dichroic person feels the light of the LED on the short wavelength side brighter than the standard observer.

The results of brightness perception efficiency with respect to the peak wavelength and full width at half maximum explained above are based on visual recognition of the elderly and one-type dichroic person by considering not only the peak wavelength but also the full width at half maximum when adopting the light source for product display. It can be shown that the performance can be improved.
For example, light sources with a peak wavelength of 530 nm or less (blue LEDs, etc.) feel brighter for older people as the full width at half maximum of the peak wavelength increases within the range of 15 to 100 nm, and for those with a single-type dichroic person in the range of 15 to 100 nm. Within the full width at half maximum, it feels brighter than a young tri-colored person. Therefore, when a light source having a spectral radiant intensity distribution with a peak wavelength of 530 nm or less is used in the display device, if a light source having a wide full width at half maximum (for example, 65 nm) is used, the brightness of the light source felt by the elderly can be reduced. It is possible to approach the brightness of the light source felt by the color vision person.

In addition, light sources with a peak wavelength of 610 nm or more (red LEDs, etc.) feel brighter for older people as the full width at half maximum of the peak wavelength becomes narrower within the range of 15 to 100 nm, and for those with a single-type dichroic person, the full width at half maximum of the peak wavelength. Is brighter as it becomes wider within the range of 15 to 100 nm. Therefore, when using a light source having a spectral radiant intensity distribution with a peak wavelength of 610 nm or more for the display device, the same peak wavelength as the first light source having a spectral radiant intensity distribution of the first full width at half maximum λ _d1 with a peak wavelength of 610 nm or more is used. And a second light source having a spectral radiant intensity distribution with a second full width at half maximum λ _d2 larger than λ _d1 in the display device, and when the elderly mode is selected, the first light source emits light, When the dichroic person mode is selected, the second light source may emit light. Then, the brightness of the light source felt by an elderly person or a type 1 dichroic person can be brought close to the brightness of the light source felt by a young tricolor sensation person.

Further, the light source 34b shown in FIGS. 1 and 2 is a first light source (blue LED or the like) having a peak wavelength λ _p1 of 530 nm or less, and the light source 34a has a peak wavelength λ _p2 (λ _p2 > λ _p1 ) of 530 nm or more. Consider a display device for elderly people as a light source (red LED or the like). In this case, the full width at half maximum λ _d1 of the peak wavelength in the first light source may be larger than the full width at half maximum λ _d2 of the peak wavelength in the second light source. Thereby, it is possible to make it easier for an elderly person to visually recognize the light source of the display device without changing the color.

Furthermore, the light source 34b shown in FIGS. 1 and 2 is a first light source (blue LED or the like) having a peak wavelength λ _p1 of 570 nm or less, and the light source 34a has a peak wavelength λ _p2 (λ _p2 > λ _p1 ) of 570 nm or more. Consider a display device for a one-type two-color person who uses a light source (such as a red LED). In this case, the full width at half maximum λ _d2 of the peak wavelength in the second light source may be larger than the full width at half maximum λ _d1 of the peak wavelength in the first light source. Since the brightness perceived efficiency BPE when the peak wavelength lambda _p2 is above 570nm in the case of the first die two color vision person becomes 1 or less, increasing the full width at half maximum of the peak wavelength for the second light source a peak wavelength lambda _p2 is above 570nm By doing so, it is possible to make the light source of the display device easily visible without changing the color for the one-type dichroic person.

  Furthermore, a plurality of light sources having the same peak wavelength and different full widths at half maximum may be provided in the display device, and a selection operation of a mode for emitting one of these light sources may be accepted, and a light source corresponding to the accepted mode may be emitted. Good. Thereby, it is possible to make the light source of the display device easily visible to the target person such as an elderly person or a color weak person without changing the color.

  In this study, the spectral radiant intensity distribution of a monochromatic LED was defined by the Gaussian function of Equations (4) and (5). However, even if the spectral radiant intensity distribution of the light source is not a Gaussian function, the spectral radiant intensity distribution is a function of wavelength λ. It is possible to calculate the brightness perception efficiency.

  In addition, when a light-emitting simulator that increases the light intensity of a light source designed for a standard user to BPE times is created, the standard user actually sees how dark the elderly and color-blind people feel. Can be confirmed. As a result, it is possible to design a display device that takes into account the reduction in brightness felt by elderly people and color-impaired people.

(8) Description of light source brightness determination method using brightness perception efficiency BPE:
When the brightness perception efficiency BPE of the target person is obtained as described above, the brightness perception efficiency is determined based on the standard brightness set for the standard user based on the brightness perception efficiency BPE. The brightness changed according to the reciprocal 1 / BPE is determined as the brightness of the LED 34.
For example, when the standard brightness of each light source 34 is set as the luminous intensity I _v (cd) according to the young tri- _{colored person} , the brightness of each light source 34 according to the visual perception of the subject is the luminous intensity I _{v — o} = I _v. / BPE (cd). Since the brightness perception efficiency BPE corresponds to the ratio of the psychophysical quantity of the subject to the psychophysical quantity of the young tri-colored person, the target luminous intensity I _v of the light source 34 is multiplied by the inverse 1 / BPE of the brightness perception efficiency. The brightness that makes the person feel the brightness felt by the young tri-colored person is determined.

As the brightness index for determining the brightness of the light source, brightness, luminous flux, illuminance, and the like can be used in addition to the luminous intensity.
For example, when the standard brightness of the light source is set as the luminance L (cd / m ² ), the luminance L _o (cd / m ² ) of the light source according to the visual perception of the subject can be set to L / BPE. . When the standard brightness of the light source is set as the light flux Φ (lm), the light flux Φ _o (lm) of the light source that matches the visual perception of the subject can be Φ / BPE. When the standard brightness of the light source is set as illuminance E (lx), the illuminance E _o (lx) of the light source in accordance with the visual perception of the subject can be set to E / BPE.

By the way, it is also assumed that the light source cannot emit light so that the brightness is represented by an amount strictly obtained by multiplying the amount of light intensity or the like representing the standard brightness by the inverse 1 / BPE of the brightness perception efficiency. The In this case, the brightness closest to the brightness represented by the strictly determined amount may be determined as the brightness of the light source that matches the visual perception of the subject. For example, when the brightness of light emitted from the light source is stepwise, the brightness closest to the brightness represented by the strictly required amount among the brightness of the plurality of stages is adjusted to the visual perception of the subject. It can be determined as the brightness of the light source. The brightness determined in this way is also included in the brightness changed according to the visual sensitivity ratio I _Lu / I _{Lu_o} with the standard brightness as a reference.

  The determined brightness of the light source 34 is close to the brightness that a standard user feels when viewing the light source 34 when the subject looks at the light source 34. Therefore, even if the color does not change, a subject such as an elderly person or a color weak person can easily view the light source 34.

(9) Description of light source brightness determination method by light source brightness determination program:
It is also possible to prepare a program for executing the above-described light source brightness determination method and cause the computer 80 to execute the program. In this case, if the non-volatile memory 84 shown in FIG. 6 stores the light source brightness determination program P1 for executing the light source brightness determination method, it is suitable for the computer 80 to execute.
FIG. 13 exemplifies processing that the computer 80 implements by the light source brightness determination program P1. When the process shown in FIG. 13 is started, the computer 80 receives an input for setting the lower limit λ _S and the upper limit λ _L of the wavelength of visible radiation (S202). If there are default values such as λ _S = 400 nm and λ _L = 700 nm, these default values may be set as λ _S and λ _L.

In S204, data representing the spectral radiation intensity I (λ) of the light source is acquired. The data to be acquired is data representing the above-described equations (4), (5), and the like. For convenience of calculation by the computer 80, the value of each spectral radiant intensity I (λ) may be acquired with the wavelength λ in a predetermined increment (for example, 1 nm increment) in the range of λ _S ≦ λ ≦ λ _L.

When using a light source having n (n is an integer of 1 or more) peak wavelengths λ _pi (i is an integer from 1 to n) and the full width at half maximum corresponding to each peak wavelength λ _pi is λ _di , 14 may be performed in S204. When starting the spectral radiant intensity distribution determination process, the computer 80 receives an input of the peak wavelength λ _pi of the light source (S302). In S304, the input of the full width at half maximum λ _di of the light source is accepted. In S306, the input of the correction coefficient I _i according to the intensity of the spectral radiation intensity at the peak wavelength is accepted. The processing of S302 to S306 can be, for example, processing for receiving an operation input of a peak wavelength value, a full width at half maximum value, and a correction coefficient value from the user of the computer 80, respectively.
In S308, the standard deviation σ _i is calculated using the above-described equation (3).

In S310, it is determined whether or not the input of λ _pi , λ _di , and I _i has been received for all peak wavelengths appearing in the spectral radiant intensity distribution of the light source. If the input has not been completed, the processing of S302 to S310 is repeated. When input for all peak wavelengths is received, data representing the spectral radiation intensity I (λ) is obtained using the above-described equation (4) (S312).

After obtaining data representing the spectral radiation intensity I (λ), the computer 80 obtains data representing the spectral luminous efficiency V _o (λ) of the subject (S206 in FIG. 13). The data to be acquired is data representing the above-described equations (7), (8), and the like. For the convenience of calculation by the computer 80, the value of each spectral luminous efficiency V _o (λ) may be acquired in the range of λ _S ≦ λ ≦ λ _L with the wavelength λ set in a predetermined step (for example, 1 nm step).

In S208, it acquires the maximum luminous efficacy of k _m to standard. k _m may use CIE maximum luminous effect of equal to 683 lm / W or the like.
In S210, the target person's maximum visual effect degree _{km_o} is acquired. k _{M_o} is above _{k m_e = 0.435k m, k m_p} = 1.380k m, or the like can be used.

In S212, the standard visual sensitivity I _Lu is calculated using the above-described equation (1). In S214, the visual sensitivity I _{lu_o} of the _subject is calculated using the above-described equation (2). For the convenience of calculation by the computer 80, the values of the respective photosensitivities I _Lu and I _{lu_o} with the wavelength λ set in a predetermined unit (for example, in _units of 1 nm) in the range of λ _S ≦ λ ≦ λ _L may be obtained.
In S216, brightness perception efficiency BPE = I _Lu — _o / I _Lu is calculated using the above-described equations (9) to (11).

In S218, a value B _m representing standard brightness set in accordance with the standard user is acquired. As B _m , a light intensity I _v (cd) set in accordance with a young tri-colored person can be used.
In S220, the brightness B _{m_o} of the light source that matches the visual perception of the subject is determined. B _{M_o} is, B _m / BPE, close to B _m / BPE, or the like can be used.

(10) Explanation of effects of light source brightness determination method and light source light emission method:
When the LED 34 shown in FIGS. 1 and 2 is caused to emit light, the light emission amount of each LED 34 is controlled by the light source brightness varying means 31 shown in FIG. 2 so that the brightness is determined according to the visual perception of the subject. To do. When the brightness of the LED 34 is changed by PWM control as shown in FIG. 3, the inverse 1 / BPE of brightness perception efficiency is set to the duty ratio of the PWM signal in the normal mode with respect to the nonvolatile memory 14 shown in FIG. The pulse width values 14b and 14c having the multiplied duty ratio may be written. The remote control device 2 performs the process shown in FIG. 7 and causes the LED 34 to emit light so that the brightness is determined according to the visual perception of the subject. Therefore, it can be said that the remote control device 2 is a display device that emits the light source with the brightness determined by the above-described light source brightness determination method.
Since the above-described light source brightness varying means 31 is provided in the remote control device 2, the LED 34 can be made to emit light with brightness that matches the visual perception of the subject without changing the LED 34.

As described above, according to the light source brightness determination method and the light source emission method, the brightness of the light source can be determined quantitatively according to the visual perception of the subject by the new concept of brightness perception efficiency. The light source that emits light can be controlled based on numerical values. Therefore, the luminance contrast between the object and the background can be increased according to the visual perception of the subject, and even if the color of the light source does not change, the subject such as an elderly person or a color weaker can easily see the display by the light source. . Of course, if there is a difference in brightness between the object and the background, an elderly person or a color-weak person can recognize the object even if the color does not change.
From the above, it is possible to make it easier for target persons such as elderly people and color-blind people to see the display on the display device using the light source without changing the color, and it is easy to realize a color universal design that takes into account the color vision characteristics of a wide range of users It becomes.

  If a personal information database is provided in the computer 80 and information indicating which color vision person corresponds to this personal information database, it corresponds to an authenticated individual after performing personal authentication such as fingerprint authentication or retina authentication. Information on color blind persons can be acquired from a personal information database. By obtaining the corresponding brightness perception efficiency from the brightness perception database, it is possible to determine the brightness of the light source according to the individual's visual perception, and to provide a display device having a light source that emits light with the brightness tailored to the individual can do.

(11) Various modifications:
By the way, as a display device to which the present invention can be applied, in addition to a remote control device for a lighting device, a remote control device for hot water supply equipment, a remote control device for bathroom equipment, and the like can be considered.
The light source to which the present invention can be applied may be a backlight for a liquid crystal display, a light source for a plasma display, an organic EL (electric luminescence), an incandescent lamp, or the like.
The standard user referred to in the present invention may be a non-young tricolor person or the like.
The subject referred to in the present invention may be a type 2 dichroic person or the like.
When the display device is used mainly in a dark place, a function or coefficient corresponding to dark place vision or twilight vision may be used as the function or coefficient for obtaining the brightness perception efficiency BPE.
Instead of _{obtaining the} brightness perception efficiency BPE, the ratio I _Lu / I _{Lu_o} of the standard photosensitivity to the subject's visual sensitivity is obtained, and the visual sensitivity of the subject is _adjusted based on this ratio I _Lu / I _{Lu_o} The brightness of the light source may be determined. The ratio I _Lu / I _{Lu_o} is the reciprocal of the brightness perception efficiency BPE, and can be said to be a multiplication factor multiplied by a value representing the brightness of the light source. Further, a value _obtained by _adding / subtracting / _dividing a predetermined value to / from BPE, a value obtained by _adding / subtracting / _dividing a predetermined value to / from I _Lu / I _{Lu_o} , and the like can be used instead of the brightness perception efficiency.

The pulse width value stored in the display device may be stored in the ROM 12 shown in FIG.
When changing the brightness of the LED, the light source brightness varying means may change the amount of current supplied to the LED, or may change the voltage applied to the LED.

The brightness perception efficiency BPE described above may be stored in a display device.
FIG. 15 shows processing performed by the remote control device (display device) according to the second embodiment. In this remote control device, it is assumed that the brightness perception efficiency BPE _elderly and BPE _protan of an elderly person and a one-type dichroic person are stored in the nonvolatile memory 14 shown in FIG. The pulse width values 14 b and 14 c for the elderly person and the one-type two-color vision person may not be stored in the nonvolatile memory 14. The process shown in FIG. 15 is started when the mode switching buttons 24a to 24c are pressed.

First, the control unit 10 acquires a normal mode pulse width command value (S402). In S402, the pulse width value 14a for the young tri-colored person may be read from the nonvolatile memory 14 and converted into a pulse width command value as necessary.
In S404, it is determined which mode has been selected.

When the mode switching button 24b is operated, the elderly mode is selected, and the brightness perception efficiency BPE _elderly for the _elderly is read from the nonvolatile memory 14 in S406. In step S408, a pulse width command value is set so that the pulse width of the PWM signal in the normal mode is 1 / BPE _elderly, which is the inverse of the brightness perception efficiency. For example, the pulse width value 14a for a young tricolor person may be multiplied by 1 / BPE _elderly and converted into a pulse width command value as necessary.
When the mode switching button 24c is operated, the one-type two-color person mode is selected, and the brightness perception efficiency BPE _protan for the one-type two-color person is read from the nonvolatile memory 14 in _S410 . In step S412, a pulse width command value for obtaining a normal mode pulse width that is 1 / BPE _protan, which is the inverse of the brightness perception efficiency, is acquired. For example, the pulse width value 14a for a young _{tricolor person may be} multiplied by 1 / BPE _protan and converted into a pulse width command value as necessary.

After S404 (during the normal mode), S408, and S412, the control unit 10 outputs the acquired pulse width command value to the pulse width control circuit 32, and performs illumination / display processing similar to S112 in FIG. S416). Then, the LED 34 that emits light at the standard brightness is changed to the brightness determined for the elderly when the elderly mode is selected, and when the one-type two-color sense mode is selected, the one-type two-color sense is selected. It is changed to the brightness determined for the person.
From the above, it can be said that this remote control device that makes the pulse width of the PWM signal a reciprocal of the brightness perception efficiency determines the brightness of the light source in accordance with the visual perception of the subject. Therefore, the process performed by the remote control device is a part of the light source brightness determination method.

  FIG. 16 is a block diagram illustrating an outline of an electric circuit of the remote control system 101 according to the third embodiment. The remote control device (display device) 102 of this embodiment does not have the pulse width control circuit 32, and the brightness of the LED 34 that emits light does not change. Therefore, the LED 34 having the brightness closest to the brightness for the subject determined by the above-described light source brightness determination method is selected from a plurality of LEDs, and the selected LED 34 is attached to the remote control device 102 to emit light. I have decided.

FIG. 17 schematically shows a light source emission method of the remote control device 102 according to the third embodiment.
In order to implement this light source emission method, first, the light source brightness database DB2 is created in the computer 80 or the like. The light source brightness database DB2 stores data of optical characteristics such as peak wavelength and full width at half maximum for each light source, and data B _i (for example, luminous intensity) representing the brightness of the light source when mounted on the remote control device 102. ) Is stored. The data B _i may be data obtained from the light intensity included in the optical characteristic data of the light source, or may be actual measurement data obtained by mounting the light source on an electric circuit provided in the remote control device 102.

When the subject's brightness perception efficiency BPE is obtained by the above-described light source brightness determination method and the LED brightness B _m — _o = B _m / BPE is determined in accordance with the subject's visual perception, first, the light source brightness database DB2 Search for. Here, B _m is a value representing standard brightness set in accordance with a standard user. When searching, an LED having the same color as the standard user LED is searched. Accordingly, the brightness closest to the brightness B _{m_o} is selected from the LEDs of the same color in the light source brightness database DB2. Next, the selected LED is mounted on the remote control device 102. As a result, the remote control device 102 is for the target person.
When the LED 34 of the remote control device 102 for the target person is caused to emit light, the brightness felt when the standard user sees the LED mounted on the remote control device for the standard user when the target person sees the LED 34. It is approaching.

  According to the third embodiment, it is possible to cause the light source of the display device to emit light with brightness according to visual perception to the target person such as an elderly person or a color weak person without providing a circuit that changes the brightness of the light source. .

  FIG. 18 shows the appearance of a remote control device (display device) 202 according to the fourth embodiment. The remote control device 202 is provided with a touch panel in which a position input device 222 is combined with a liquid crystal panel 220 on the front surface. On the liquid crystal display surface 221 of the liquid crystal panel 220, various operation buttons 23a to 23e and 24a to 24c having functions similar to those of the first embodiment and a plurality of display areas 221a corresponding to the LEDs 34b of the first embodiment are provided. Is provided. Each display area 221a has a narrow display area with a viewing angle of less than 2 ° when viewed from a position when the remote controller 2 is operated (for example, a distance of 50 cm). The functions of the operation buttons 23a to 23e and 24a to 24c are realized by the position input device 222 that detects that the corresponding position of the liquid crystal display surface 221 is pressed.

As in the remote control system 201 shown in FIG. 19, in the remote control device 202, the liquid crystal driver 228, the position input device 222, and the light source brightness varying means 31 are connected to the control unit 10.
The liquid crystal driver 228 drives the liquid crystal panel 220 according to the control of the control unit 10 to display the operation buttons 23a to 23e, 24a to 24c and the display area 221a on the liquid crystal display surface 221. The liquid crystal panel 220 is provided with a position input device 222 and is irradiated with light from a backlight (light source) 234 from behind. As the position input device 222, a touch pad or the like can be used.

  A backlight 234 is connected to the light source driving circuit 33 of the light source brightness varying means 31. The backlight 234 is assumed to be a white LED in which a red chip, a green chip, and a blue chip are incorporated. Similar to the LED 34 of the first embodiment, the backlight 234 emits light by inputting a pulsed current from the light source driving circuit 33. This current has a pulse width corresponding to the pulse width command value from the control unit 10. A pulse width control circuit 32 that supplies a PWM signal to the light source drive circuit 33 inputs a pulse width command value from the control unit 10 and generates a PWM signal having a pulse width corresponding to the pulse width command value. Accordingly, the liquid crystal display surface 221 irradiated with the light from the backlight 234 becomes brighter as the duty ratio of the PWM signal increases, and becomes darker as the duty ratio of the PWM signal decreases. If the influence of the transmission characteristics of the light transmitted through the liquid crystal display surface 221 is small, the liquid crystal display surface 221 has a brightness substantially proportional to the duty ratio of the PWM signal.

Therefore, in the same manner as in the first embodiment, based on the brightness perception efficiency BPE of the subject, the reciprocal 1 / BPE of the brightness perception efficiency is set based on the standard brightness set for the standard user. The brightness changed accordingly may be determined as the brightness of the backlight 234. For example, if the standard brightness of the backlight 234 is set to the luminance L (cd / m ² ) in accordance with the young tri-colored person, the brightness of the backlight 234 in accordance with the subject's visual perception is the luminance L _o ( cd / m ² ) = L / BPE (cd / m ² ). Of course, the brightness of the backlight may be determined in accordance with the visual perception of the subject using the brightness, luminous flux, illuminance, and the like of the backlight.
The determined brightness of the backlight 234 is the liquid crystal display surface that a standard user irradiates with the backlight 234 having the standard brightness when the subject looks at the liquid crystal display surface 221 irradiated with this brightness. It is close to the brightness you feel when you look at 221. Therefore, even if the color does not change, a subject such as an elderly person or a color weak person can easily view the display area 221a of the liquid crystal display surface 221.

From the above, it is possible to make it easier for the subject, such as the elderly and the color-blind, to visually recognize the display on the display device using the backlight without changing the color, and to realize a color universal design that takes into account the color vision characteristics of a wide range of users It becomes easy.
Although the above-described backlight has been described as a light source of a three-color LED system, a backlight such as a blue-yellow pseudo white light emitting diode using a blue chip and a phosphor can also be used. For backlights such as pseudo-white light emitting diodes, the brightness perception efficiency can be obtained if a function of the spectral radiant intensity is prepared, and the brightness of the backlight is quantitatively determined according to the visual perception of the subject. be able to.

When evaluating the brightness for a monochromatic light source having a wide area (viewing angle of 2 ° or more), the brightness spectral luminous efficiency V _b (shown in Appendix 2 (reference) of JIS S0031: 2004). It has been proposed to use λ). Therefore, when the light source is monochromatic light and has a wide viewing angle, the brightness spectral luminous efficiency V in accordance with JIS S0031: 2004 Annex 2 (reference) is used instead of the spectral luminous efficiency V _o (λ) described above. _b (λ) may be used.

Here, the peak wavelength of the monochromatic light source is λ _p (nm), the full width at half maximum corresponding to this peak wavelength is Δd (nm), the spectral radiant intensity of the monochromatic light source as a function of the wavelength λ is I (λ), and the wavelength λ V _b (λ) is the standard brightness spectral luminous efficiency as a function of V _{b_o} (λ), the brightness spectral luminous efficiency of the subject as a function of wavelength λ, and the standard brightness spectrum luminous efficiency V _b (λ) k a luminous effect at a wavelength which is maximized _m, subject brightness spectral luminous efficiency _V b_o (λ) k m_o a luminous effect at a wavelength which is maximum, Then, the brightness perception efficiency BPE is expressed by the following equation.
Therefore, when determining the brightness according to the visual perception of the subject for a monochromatic light source having a wide area with a viewing angle of 2 degrees or more, the brightness perception efficiency BPE is obtained using the above equation (12), and this brightness is determined. The brightness changed according to the inverse 1 / BPE of the perception efficiency may be determined as the brightness of the monochromatic light source.
The above expression (12) is an expression obtained by simplifying the _luminous efficiency ratio I _{Lu — o} / I _Lu . Therefore, _{obtaining the} brightness perception efficiency BPF according to the equation (12) is included in _obtaining the ratio between the standard luminous efficiency I _Lu and the subject's luminous efficiency I _{Lu_o according} to the present invention.

Of course, the brightness of the light source having a wide viewing angle is determined using the brightness spectral luminous efficiency V _b (λ) when the brightness is to be evaluated very strictly. Therefore, when it is not necessary to strictly evaluate the brightness so far, the brightness of the light source having a wide viewing angle may be determined using the spectral luminous efficiency shown in the first embodiment.

Note that the above-described basic actions and effects can be obtained even with an apparatus and method that have only the constituent elements according to the independent claims without the constituent elements according to the dependent claims.
In addition, the present invention is not limited to the above-described embodiments and modifications, and the configurations disclosed in the above-described embodiments and modifications are mutually replaced or the combination is changed, the known technology, and the above-described configurations. Configurations in which the respective configurations disclosed in the embodiment and the modified examples are mutually replaced or combinations are changed are also included.

1, 101, 201 ... remote control system,
2, 102, 202 ... remote control device (display device),
10 ... Control unit, 24a-24c ... Mode switching button,
31 ... Light source brightness variable means, 32 ... Pulse width control circuit, 33 ... Light source drive circuit,
34 ... Light emitting diode (light source),
220 ... Liquid crystal panel, 234 ... Back light (light source),
DB1 ... Brightness perception efficiency database.

Claims (4)

A light source brightness determination method for a display device that determines the brightness of the light source according to the visual perception of a subject with reference to a standard brightness set for a standard user for the light source of the display device,
(A) The wavelength of light is λ, the spectral radiant intensity of the light source as a function of the wavelength λ is I (λ), and the spectral luminous efficiency of the subject as a function of the wavelength λ is V _o (λ ), a spectral luminous efficiency and has been standardized as a function of the wavelength lambda V (lambda), the luminous efficacy at a wavelength at which the spectral luminous efficiency V to the standard (lambda) is maximum k _m, the The visual effect efficiency at the wavelength at which the spectral luminous efficiency V _o (λ) of the subject is the maximum is _{km_o} , the wavelength on the short wavelength side of the visible radiation is λ _S , and the wavelength on the long wavelength side of the visible radiation is λ _L When the standard photosensitivity
And the visual sensitivity of the subject
Obtaining a value corresponding to the ratio of
(B) Based on the value obtained in the step (A), the brightness changed according to the ratio I _Lu / I _{Lu_o} of the I _{Lu to} the I _{Lu_o} with the standard brightness as a reference brightness of the light source And determining the brightness of the light source of the display device. A light source having n (n is an integer of 1 or more) peak wavelengths λ _pi (i is an integer from 1 to n) and a full width at half maximum corresponding to each peak wavelength λ _pi being λ _di. Use
In step (A), the standard deviation σ _i corresponding to each peak wavelength λ _pi is calculated.
And the spectral radiant intensity I (λ) is defined as I _i , which is a correction coefficient for the radiant intensity corresponding to each peak wavelength λ _pi.
The light source brightness of the display device according to claim 1, wherein a value corresponding to a ratio between the I _Lu and the I _{Lu_o} is obtained using the determined spectral radiant intensity I (λ). Decision method. A light source emission method for a display device that emits the light source at a brightness determined by the light source brightness determination method for a display device according to claim 1 or 2,
The display device is provided with light source brightness variable means for changing the brightness according to the input to emit the light source,
By performing input corresponding to the brightness determined in step (B) to the light source brightness variable means, the brightness of the light source that emits light at the standard brightness is determined in step (B). A light source light emitting method for a display device, characterized in that the brightness is changed to a specified brightness.   A light source having a brightness closest to the brightness determined by the light source brightness determination method for a display device according to claim 1 or 2 is selected from a plurality of light sources, and the selected light source is selected for the display device. A light source light emitting method for a display device, wherein the light source emits light by being mounted.