JPS6148731A - Light waveform generating device - Google Patents

Abstract

PURPOSE:To set the frequency of light easily and accurately by receiving a pulse signal from an oscillation part and then comparing a signal corresponding to the light output of a light source part with data constituting a light waveform, and performing feedback control over the intensity of light outputted from the light source. CONSTITUTION:Plural data for controlling the light output with time are stored in a memory 10 and those data are outputted to a D/A conversion part 11 and an arithmetic part 14 successively. Converted data are supplied to the light source part 12; the majority of the output light of the light source part 12 is seen with an observer's eye 13 and the remainder is guided to a photodetection part 16. The signal of the photodetection part 16 is outputted to the arithmetic part 14 through an A/D conversion part 16. A data input part 19 inputs plural data constituting the light waveform and stores them in a memory 18. The arithmetic part 14 has a pulse signal from the oscillation part 17 and compares the signal from the conversion part 15 with data of the memory 18 to correct data in the memory 10. Thus, the time required for single-time feedback control is determined by the pulse signal from the oscillator, so that the light frequency is set accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical waveform generator for experimentally examining the response characteristics of the visual system to modulated light.

Conventional Structures and Their Problems In recent years, with the spread of discharge lamps, an increasing number of facilities are illuminated with light whose intensity varies over time. Furthermore, as office automation progresses, opportunities to view CRT displays have increased, and the characters on these CRT displays also vary in intensity over time. When viewing light whose intensity fluctuates over time as described above (hereinafter referred to as modulated light), flicker may be perceived depending on the frequency and waveform of the light. Flicker is closely related to the discomfort caused by lighting and displays.
This is an important item that determines the quality of discharge lamps and displays. However, at present, the response characteristics of the visual system to modulated light are not clear, and a quantitative relationship between the frequency and waveform of light and the discomfort caused by flicker has not been obtained. As mentioned above, it is thought that the chances of seeing modulated light will increase more and more in the future, so it is desired to establish a technology for evaluating the discomfort caused by flicker based on the temporal response characteristics of the visual system.

As described above, various experimental devices having the function of generating arbitrary light waveforms have been proposed for experimental investigation of the response characteristics of the visual system to modulated light. As an example, FIG. 1 shows a block diagram of an apparatus using a method of shaping an optical waveform by feedback control. In FIG. 1, 1 is the first memory, 2 is the D/A converter, 3 is the light source, 4 is the observer's eye, and 5
6 is an arithmetic unit, 6 is an A/D converter, 7 is a light receiving unit, 8 is a second memory, and 9 is a data input unit.

The operation of the conventional optical waveform generator will be described below with reference to FIG.

The first memory 1 stores a plurality of pieces of data for temporally controlling the optical output, and these data are sequentially output to the D/A converter and the arithmetic unit 6. now,
For explanation, n pieces of data are stored in the first memory 1,
Assume that the first data (1≦1≦n) among them is output.

The D/A converter 2 performs D/A conversion on the first data in the first memory 1 and outputs it to the light source 3. As an example,
In the case where the light output from a light bulb lit with direct current is changed using an electro-optic light modulation element, the relationship between the intensity of the light output generated from the light source section 3 with respect to the signal intensity from the D/A conversion section 2 is shown. Shown in Figure 2.

Most of the light output from the light source section 3 is given to the observer's eye 4 for visual experiments, and a part of the light output is guided to the light receiving section 7. The light receiving section 7 outputs a signal corresponding to the intensity of the optical output from the light source section 3 to the A/D converting section 6.

The A/D converter 6 performs A/D conversion on a signal corresponding to the intensity of the optical output from the light source 3 and outputs it to the arithmetic unit 5 . The data input section 9 inputs a plurality of pieces of data constituting an optical waveform, and outputs these data to the second memory 8. Note that the number of data forming the optical waveform is n in this description. The second memory 8 configures the optical waveform from the data input section.
The first data corresponding to the first data output from the first memory 1 is output to the arithmetic unit 5. The calculation unit 5 receives the signal from the human/D conversion unit 6, the i-th data in the first memory 1, and the second memory 8.
input the i-th data of , and correct the first data of the first memory 1 based on the result of comparing the signal from the A/D converter 6 and the first data of the second memory 8. do. That is, when the intensity of the optical output generated from the light source section 3 monotonically increases with respect to the signal intensity from the D/A converter section 2 as shown in FIG. is larger than the first data in the second memory 8, comb the first data in the first memory 1 with a small comb.
If the signal from the D converter 6 is smaller than the first data in the second memory 8, the first data in the first memory 1 is increased. Conversely, when the intensity of the optical output generated from the light source section 3 monotonically decreases with respect to the signal intensity from the D/A converter section 2, the signal from the human/D converter section 6 is more sensitive to the second memory. If the data is larger than the first data in memory 8, increase the first data in memory 1, and
If the signal from the /D converter 6 is smaller than the first data in the second memory 8, the first data in the first memory 1 is made smaller. The thus modified data in the first memory 1 is output to the first memory. In addition,
In the first memory 1, after storing the corrected first data returned from the calculation unit 5 in the area where the original first data was stored, the 1+1st data is transferred to D/A.
It is output to the conversion section 2 and the calculation section 5. However, if 1+1 exceeds n, the first data is output. In this optical waveform generator, the /A converter 2 as shown in FIG.
There is a non-linear relationship between the signal from the D/A converter and the optical output from the light source 3, and the light output from the light source 3 varies depending on whether the signal from the D/A converter is increased or decreased. Even if the outputs are different, it is possible to obtain the optical output according to the n data forming the optical waveform input from the data input section.

However, in the optical waveform generator configured as described above, the time required for one feedback control to correct the first data in the first memory is limited to the time required for the first memory, the second memory, and the arithmetic unit. It depends on the processing speed specific to the computer that constitutes the data input section. Therefore, if you want to change the frequency of the generated light, create a routine that performs unnecessary calculations during the feedback control program, and adjust the amount of calculation processing to reduce the time required for one feedback control. A common method was to adjust and change the frequency of light. However, with this method, it is necessary to determine the relationship between the amount of calculation processing and the frequency of light in advance through cut-and-try methods, and the problem is that it takes time to make adjustments for practical use as an experimental device. had. In addition, because the time was adjusted based on the amount of calculation processing, it was not possible to set an accurate light frequency. For example, in a device that takes about 500 microseconds to control one feed, and about 60 microseconds to perform arithmetic processing for one time adjustment, the accuracy of time adjustment is only about 10%. . In addition, if you want to set the frequency of light to a different value, you need to stop feedback control and change the amount of arithmetic processing for the above-mentioned time adjustment. It was extremely difficult to evaluate. Furthermore, when changing the computer model to one with a different processing speed, it was necessary to recalculate the relationship between the amount of arithmetic processing required for time adjustment and the frequency of light.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned problems, and an object of the present invention is to provide an optical waveform generator that can easily and accurately set the frequency of light.

Structure of the Invention: An oscillator that generates a pulse signal with a set frequency, and after receiving the pulse signal from the oscillator, a signal corresponding to the optical output from the light source and data constituting the optical waveform are compared. This is an optical waveform generator characterized by feedback controlling the intensity of light output from a light source section and modifying data to obtain an arbitrary optical waveform, and which allows the frequency of light to be set simply and accurately. be able to.

DESCRIPTION OF EMBODIMENTS FIG. 3 is a block diagram of an optical waveform generator according to an embodiment of the present invention. In FIG. 3, 10 is a first memory, 11 is a D/A converter, 12 is a light source, and 13
1 is the observer's eye, 14 is the calculation unit, 15 is the A/D conversion unit, 1
6 is a light receiving section, 17 is an oscillating section, 18 is a second memory, 19
is the data input section.

The operation of the optical waveform generator of this embodiment configured as described above will be described below with reference to FIG.

The first memory 10 stores a plurality of pieces of data for temporally controlling the optical output, and these data are sequentially output to the D/A converter 11 and the arithmetic unit 14. Now, the n pieces of data described are stored in the first memory 1.
Suppose that the data is stored in ``o'' and the first data (1≦1≦n) among them is output. In the D/A converter 11, the first
The first data in the memory 10 is converted into D/A i and outputted to the light source section 12. Most of the light output from the light source section 12 is given to the observer's eye 13 for visual experiments, and a portion of the light output is guided to the light receiving section 16. The light receiving section 16 is the light source section 12
A signal corresponding to the intensity of the optical output from the A/D converter 15 is output to the A/D converter 15. The A/D converter 15 A/D converts a signal corresponding to the intensity of the optical output from the light source 12, and
Output to 4. The data input section 19 inputs a plurality of pieces of data constituting an optical waveform, and outputs these data to the second memory 18.

In this description, the number of data forming the optical waveform is n. The second memory 18 stores n pieces of data constituting the optical waveform from the data input section, and stores n pieces of data that constitute the optical waveform from the data input section.
The second data is output to the calculation unit 14. FIG. 4 is a flowchart showing the contents of calculations performed by the calculation section when the relationship between the signal intensity from the D/A conversion section 11 and the light output generated from the light source section 12 is monotonically increasing. In FIG. 4, the calculation section 14 waits for a pulse signal from the oscillation section 1. After receiving the above pulse signal, input the signal from the A/D converter 15, the first data of the first memo IJ 10, and the i@th data of the second memory 18,
Based on the result of the ratio 11i2 of the signal from the D converter 15 and the first data of the second memory 18,
Correct the first data of 0. That is, since the intensity of the light output generated from the light source section 12 monotonically increases with respect to the signal from the D/person conversion section 11, the A/D conversion section 1
If the signal from the A/D converter 16 is larger than the first data in the second memory 18, the data in the first memory 1001 is made smaller, and the signal from the A/D converter 16 is larger than the first data in the second memory 18. If the data is smaller than the first data in the first memory 10, the first data in the first memory 10 is increased. The thus modified data in the first memory 10 is output to the first memory 10. Note that in the first memory 1o,
After storing the corrected first data returned from the calculation unit 14 in the area where the original first data was stored, the 1+1st data is output to the D/A conversion unit 11 and the calculation unit 14. . However, if 1+1 exceeds n,
Output the first data.

As described above, according to this embodiment, the oscillation unit 1
By waiting for the pulse signal from 7, the time required for one feedback control is determined by the frequency of the pulse signal from the oscillator, and the frequency of the light can be determined simply and accurately. Therefore, no adjustment is necessary before using the device. Furthermore, when it is desired to change the frequency of light, there is no need to stop feedback control. Furthermore, in this embodiment, similar effects can be obtained even if computers with different processing speeds are used.

Although this embodiment relates to a device that arbitrarily generates a light waveform, it can also be used in a device that shapes a general electrical signal waveform or acoustic waveform by feedback control, in which the light source section is connected to the signal generation section or the sound generation section, respectively. Similar effects can be expected by replacing the light receiving sections with electrical signal monitors or microphones.

Effects of the Invention The optical waveform generator of the present invention can easily and accurately set the frequency of light by waiting for a pulse signal from the oscillation section, which is the calculation section, which generates a pulse signal at a set frequency. Its practical value is great.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional optical waveform generator, FIG. 2 is a diagram showing the relationship between the signal intensity from the D/A converter and the optical output from the light source, and FIG. 3 is a diagram of the embodiment of the present invention. FIG. 4, which is a block diagram of the example optical waveform generator, is a flowchart showing the processing contents in the arithmetic unit of this embodiment. 1Q...First memory, 11...D/
A conversion section, 12... Light source section, 13...
Observer's eye, 14... Calculation unit, 15...
・A/D conversion section, 16... Light receiving section, 17.
...Oscillator, 18...Second memory, 1
9...Data input section. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] After receiving the pulse signal from the oscillator that generates a pulse signal of a set frequency, the signal corresponding to the optical output from the light source is compared with the data forming the optical waveform. An optical waveform generator comprising an arithmetic unit that corrects data for feedback control of the intensity of light output from a light source unit.