JPH042892B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for determining whether or not various displays, including light sources for illumination, are flickering by photometric means.

In recent years, in the field of lighting, various discharge lamps have been used for indoor and outdoor lighting. However, there is a problem in that flickering can sometimes be felt under discharge lamp lighting that is turned on using a commercial power source. As a prerequisite for developing and manufacturing flicker-free discharge lamps,
It was necessary to determine whether or not the illumination light from the discharge lamp caused flickering.

Furthermore, in the field of displays, opportunities to use CRT displays are increasing due to advances in office automation. Especially the recent
Among CRT displays, positive display mode (a mode in which dark characters are displayed on a bright background) has become popular because (1) the characters are easier to read, and (2) there is less influence from reflections. . However, in this mode, since the entire screen is bright, there is a problem in that it is easy to perceive flickering. Therefore, in order to create a CRT display with a positive display without flickering, we
It was necessary to determine whether or not flicker was perceived in response to the light emitted from the display.

In this way, for light from a light emitter (light source),
A flicker threshold determination device for determining whether the light is flickering has been desired.

BACKGROUND ART A conventional apparatus for determining the presence or absence of flickering will be described with reference to FIG. In Fig. 3, 1 is a light receiving section, 2
3 is a fundamental wave detection section, 3 is an integration section, 4 is a division section, 5 is an arithmetic section, and 6 is a display section. The light receiving unit 1 receives light from a light source and converts it into an electrical signal corresponding to fluctuations in light intensity. A signal from the photoreceiver 1 is input to a fundamental wave detection section 2 and an integration section 3. The fundamental wave detection unit 2 outputs a signal A corresponding to the frequency value of each frequency included in the frequency band in which humans perceive flickering, and a signal B corresponding to the frequency component thereof. Further, the integrating section 3 outputs a signal corresponding to the temporal average value of the light intensity. The dividing unit 4 calculates the degree of amplitude modulation at each frequency included in the frequency band in which humans perceive flickering from the signal B from the fundamental wave detection unit 2 and the signal from the integrating unit 3.
The signal from the division section 4 and the signal A from the fundamental wave detection section 2 are input to the calculation section 5, which has a frequency characteristic that approximates the transfer function of the amplitude modulation degree of optical stimulation in the human eye as shown in FIG. However, if some of the frequency components of the light source have an amplitude modulation factor larger than that which humans perceive as flickering, a positive (or negative) signal is output; otherwise, a zero signal is output. Output. The display unit 6 displays that there is flickering when the signal from the calculation unit 5 is positive (or negative), and displays that there is no flickering when the signal is zero. Note that in the human eye, the value of the degree of amplitude modulation at the threshold for perceiving flickering differs depending on the temporal average value of the light intensity. For example, in FIG. 4, the upper curve a is a transfer function of the degree of amplitude modulation of the human eye measured under a condition where the temporal average value of the light intensity is larger than the lower curve b. Since the shape of this curve is determined by the temporal average value of the light intensity, the frequency characteristics of the calculation section 5 are changed by the signal from the integration section 3.

Problems to be Solved by the Invention The frequency characteristics of the arithmetic unit 5 need to be changed along with the temporal average value of the light intensity, resulting in a problem that the device is complicated and expensive.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention aims to change the value of the fundamental wave component of temporal fluctuations in intensity of light from a light source and the transmission characteristics of optical stimulation to the human eye at the fundamental frequency. It is designed to compare with the value.

Effects According to the present invention, the flicker threshold can be determined by the above-described means without depending on the temporal average value of the light intensity. According to the present invention, a determination device having a simple and inexpensive configuration can be provided.

Embodiment Hereinafter, a block configuration of an apparatus for determining the presence or absence of flickering in an embodiment of the present invention will be explained based on FIG. In FIG. 1, 7 is a light receiving section, 8 is a fundamental wave detecting section, 9 is a calculation section, and 10 is a display section.

Hereinafter, the operation of the embodiment of the present invention will be explained based on FIG. The light receiving unit 7 receives the light from the light source,
Converts changes in light intensity into electrical signals. The signal from the photoreceiver 7 is input to the fundamental wave detection section 8,
A signal A corresponding to the value of the frequency of the fundamental wave in the fluctuation of the optical intensity and a signal B corresponding to the value of the fundamental wave component of the fluctuation in the optical intensity are output. These signals A and B are input to the calculation section 9. A function corresponding to the transfer characteristic of optical stimulation in the human eye is input to the calculation unit 9. At frequencies above 10Hz,
It is known that the flicker threshold can be approximately determined by the fundamental wave component, regardless of the temporal average value of the light intensity (for example, J.Opt.Soc.Am., 61
(4) p537-546 (1971) Therefore, the function input to the calculation unit 9 should be such that the frequency component at the flicker threshold is uniquely determined for the frequency as shown by the solid line in Figure 2. It is a function.

This function is a frequency band in which the transfer functions of the fundamental wave components of the human eye measured under various temporal average values of light intensity have approximately the same value, as shown by the dashed line in Figure 2. It is obtained by concatenating. The dot-dash line in FIG. 2 indicates that the higher the curve, the lower the temporal average value of the light intensity. Depending on the temporal average value of the light intensity, the transfer characteristics of the fundamental wave in the flicker region may differ from the solid line in Figure 2 even at frequencies of 10 Hz or higher, but in such cases, the second It is below the curve shown by the solid line in the figure. That is, since the value is lower than the transfer characteristic shown by the solid line in FIG. 2, it can be said that the function shown by the solid line in FIG. 2 is a safe function in determining flicker. The calculation unit 9 reads the value of the frequency component at the flicker threshold at the frequency indicated by the signal A from the function shown in FIG. If signal B is smaller, a zero signal is output. The display section 10 displays that there is flickering when the signal from the computing section 9 is positive (or negative), and displays that there is no flickering when the signal from the computing section 9 is zero.

Effects of the Invention As is clear from the above description, according to the present invention, the presence or absence of flickering can be determined regardless of the temporal average value of light intensity, and therefore has great practical value.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a device for determining the presence or absence of flickering in an embodiment of the present invention, Fig. 2 is a graph showing a function corresponding to the transfer characteristics of optical stimulation in the human eye, and Fig. 3 is a block diagram of a conventional example. The configuration diagram, FIG. 4, is a graph of the transfer function of the amplitude modulation degree of optical stimulation in the human eye. 7... Light receiving section, 8... Fundamental wave detection section, 9... Calculating section, 10... Display section.

Claims (1)

[Scope of Claims] 1. A light receiving section that receives light from a light source, and a signal A that receives a signal from the light receiving section and that corresponds to the fundamental frequency of the light intensity and a signal B that corresponds to the fundamental wave component of the light intensity. a fundamental wave detection unit that outputs the signal A and the signal B, and a calculation unit that receives the signal A and the signal B and compares the value of the fundamental wave component of the light intensity with the value of the transfer characteristic of the fundamental wave component in the human eye at the fundamental frequency. , and a display unit that displays a signal from a calculation unit. 2. The device for determining the presence or absence of flickering according to claim 1, wherein the arithmetic unit uses light from a light source having a fundamental frequency of 10 Hz or more.