JPH0441671Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is based on the test chart (EIAJ) for adjusting distortion, shift, clarity, etc. of TV screens.
This paper relates to color viewing for optically adjusting color cameras using test charts, various test charts specified by NHK, etc., and particularly to frizzless color viewing.

Color viewers have been widely used to adjust color cameras using test charts, but conventional color viewers require commercial power (50Hz, 60Hz) to be used to illuminate the test charts on the screen. Because the current is applied as it is, flickering occurs in the fluorescent light, and when the test chart is taken with a color camera consisting of a CCD, image pickup tube, etc., rasterization occurs on the monitor TV, which may be interpreted as noise and difficult to adjust. I had a lot of flaws. Especially when it comes to high-resolution test charts, the effects of flicker from fluorescent lights are a fatal flaw.

Therefore, the object of this invention is to provide a frizzless color viewer that is free from the above-mentioned drawbacks.

This idea will be explained below.

Figures 1A and 1B show the appearance of a color viewer that is an embodiment of this invention.The main body of the color viewer is approximately rectangular parallelepiped, and the front side serves as a screen 1 on which a test chart is placed. There is.

On the other hand, the internal structure of the color viewer is as shown in Fig. 2, and a power cord 11 is connected to the back of the box 10 that constitutes the color viewer main body, and is used to supply power to the fluorescent lamp and internal circuitry described later. In addition, a pair of fluorescent lamps 12 and 13 are arranged close to each other in parallel directly below the top surface of the box 10, and one fluorescent lamp 13 is arranged directly above the bottom surface of the box 10.
A pair of fluorescent lamps 14 and 15 are arranged close to each other in parallel. The upper fluorescent lamps 12 and 13 and the lower fluorescent lamps 14 and 15 are placed at different levels and parallel to each other, and the bottom of the box 10 between the fluorescent lamps 13 and 15 is A reflecting plate 20 having a triangular cross section as shown in FIGS. 3A and 3B is arranged along each fluorescent lamp, and between the fluorescent lamps 12 and 13 and between the fluorescent lamps 14 and 15. Reflection plates 21 and 22 each having a rectangular cross section as shown in FIGS. 4A and 4B are arranged along the fluorescent lamps, respectively.

Here, the reflecting plate 20 is an elongated structure with a triangular cross section as shown in FIGS. A non-reflective area 20B is provided, and the mirror-treated reflective area 20A reflects light from the fluorescent lamp. The ratio of the length B of one side of the reflector to the length A of the non-reflection area 20B from the top is about 5:3. Further, as shown in FIGS. 4A and 4B, the reflector plate 21 (or 22) is an elongated cylindrical structure with a square cross section, and a non-reflective area 21B is chromatized in the center in the longitudinal direction. The light reflecting area 21 is formed by mirror-finishing both ends.
It is set as A. The ratio of the length A of the non-reflection region 21B in the longitudinal direction to the length B of the reflection plate 21 in the longitudinal direction is approximately 2:5.

Furthermore, a screen structure forming a screen 1 is attached to the front of the box 10, and this screen structure is attached to a rectangular acrylic diffusion plate 3.
1 and a transparent glass plate 32 laminated on this acrylic diffuser plate 31, and on the back side of the acrylic diffuser plate 31, there are four auxiliary reflectors 33 to 33 along the boundary line forming the screen 1. 36 is attached, and a fluorescent lamp 1 is installed outside the auxiliary reflectors 33 to 36.
The light from 2 to 15 is designed not to be scattered. Note that the acrylic diffuser plate 31 and these auxiliary reflectors 33
The relationship between the mounting positions of the auxiliary reflectors 33 to 36 is as shown in FIG. Mirror-finished. This kind of screen structure is box 10
Auxiliary reflecting plates 33 to 36 are attached to the front surface of the screen so as to face inward, and a test chart is placed on the top surface of a glass plate 32 that forms the screen 1.

By the way, the built-in circuit wiring is as shown in Figure 6, for example, and the AC power (100V, 50Hz or 60Hz) supplied from the power cord 11 is
It passes through a fuse 40, is rectified by a rectifier 42, is converted into a DC voltage Vo, and is applied to a high frequency oscillator 50 forming a high frequency power source. Further, the output of the rectifier 42 is smoothed by a capacitor C1, and the output of the high frequency oscillator 50 is applied to a primary winding W2 of a transformer 51. The high-frequency oscillator 50 includes a transistor Q serving as an oscillation source, a capacitor C3 connected between the emitter and collector of the transistor Q, resistors R1 and R2, a diode, and a capacitor C2 connected between the base and emitter of the transistor Q. and a resistor R3 connected between the base and collector,
The oscillation output of this high frequency oscillator 50 (for example,
18000Hz) is the secondary winding W3 to W6 of transformer 51
The current is applied from the fluorescent lamps 12 and 13 to the AC excitation windings W _a1 and W _a2 of the saturation reactor circuit 43.

Here, to explain the operating principle of the saturation reactor circuit 43 as shown in FIG. 7, a DC excitation winding Wd is wound around the center of the core of a saturation reactor (ferrite core) 431 laminated with steel plates, and a DC voltage is Vd
is applied through the variable resistor VR, and the AC excitation windings W _a1 and _{W a2} are wound in series at both ends and are magnetically coupled _.
The outputs from terminals T3 and T4 drive both ends of the fluorescent lamps 12 and 13 using the wiring connections shown in FIG. When the DC voltage Vd is 0, that is, when not energized, the impedance of the saturation reactor 431 reaches its maximum value, so that the brightness of the fluorescent lamps 12 and 13 connected between the terminals T3 and T4 becomes the minimum. Also,
When the value of the DC voltage Vd is increased, the saturation reactor 431 finally becomes saturated, and its impedance becomes the minimum value, so that the brightness of the fluorescent lamps 12 and 13 connected between the terminals T3 and T4 becomes maximum. . From this, by changing the voltage Vd applied to the DC excitation winding Wd of the saturation reactor circuit 43 or the variable resistor VR connected thereto, it is possible to control the fluorescent lamps connected to the AC excitation windings W _a1 and W _a2 . 1
The brightness of 2 and 13 can be changed. At the same time, the color temperature of the fluorescent lamps 12 and 13 can also be changed. The above also applies to the fluorescent lamps 14 and 15.

Here, a rotating shaft for changing the variable resistor VR or DC voltage Vd mentioned above protrudes in front of the screen 1, and by turning the dimming knob 8 attached to the tip, the DC excitation winding The voltage applied to Wd can be changed. In addition, the circuit shown in Fig. 6 is mounted on a printed board, etc., and the reflector 2
0 and the bottom of the box 10.

In such a configuration, an operator or the like turns on the power switch 5 and places the test chart on the screen 1 via the chart holding plates 6 and 7, so that the irradiated light from the turned on fluorescent lamps 12 to 15 is directly irradiated. The test chart is reached through the acrylic diffuser plate 31 and the glass plate 32, and the reflector plates 20, 21, 2
It is also irradiated by the reflected light from the second reflective area. Furthermore, the glass plate 32 is also
Since the test chart above is illuminated, the illuminance is extremely uniform.

And the fluorescent lamps 12 to 15 that are the light source
is the high frequency power source from the high frequency oscillator 50 (approximately
Since it is driven at a frequency of 18,000 Hz), there is no flicker in the light that illuminates the stetochaat, which affects when taking pictures. The higher the high-frequency oscillation frequency, the better for frizz-free performance, but when it exceeds 20,000Hz, high-frequency sound is produced and noise becomes a problem. As a result of experiments, the noise on the monitor screen was minimized at around 18000Hz for CCD and image pickup tube cameras. Therefore, in this invention, the oscillation frequency of the high frequency oscillator 50 is set to approximately 18000 Hz. Also, variable resistor VR
Alternatively, by turning the dimming knob 8 that changes the DC voltage Vd, the winding Wd of the saturation reactor circuit 43
Since the magnitude of the DC voltage applied to the fluorescent lamps 12 to 15 changes, the brightness of the fluorescent lamps 12 to 15 also changes, allowing desired dimming to be achieved. At the same time, the color temperature can also be varied (e.g. in the 150°K range).

In addition, in the above embodiment, the high frequency oscillator is composed of a transistor, a resistor, and a capacitor.
Various known oscillators can be used.

As mentioned above, according to the color viewer of this invention, the built-in fluorescent lamp is lit by a high frequency power source of approximately 18000Hz, so even when shooting with a color camera such as a CCD, no raster appears on the screen. You can use the test chart to make adjustments to your color camera.

[Brief explanation of the drawing]

Figure 1A is a front view of the color viewer of this invention, Figure B is a side view thereof, Figure 2 is a cross-sectional view of the color viewer of this invention, Figures 3A, B, and 4.
Figures A and B are structural diagrams of the reflector used in this invention, Figure 5 is a plan view of the screen structure used in this invention, Figure 6 is a wiring diagram showing an embodiment of this invention, and Figure 7 is a FIG. 3 is a diagram for explaining the operation of the saturation reactor circuit used in the color viewer of this invention. 1... Screen, 2... Handle, 3, 4... Rubber feet, 5... Power switch, 6, 7... Chart presser plate, 8... Dimming knob, 10... Box, 1
1...Power cord, 12-15...Fluorescent lamp, 20
~22...Reflector, 31...Acrylic diffuser, 3
2...Glass plate, 33-36...Auxiliary reflecting plate, 4
2... Rectifier, 43... Saturation reactor circuit, 5
0...High frequency oscillator.

Claims (1)

[Scope of utility model registration request] Place the test chart on the screen and optically
In a color viewer that adjusts a color camera such as a CCD or an image pickup tube, at least one pair of fluorescent lamps arranged side by side illuminates the screen from the inside with approximately 18,000 lights each.
A fritscare-less color viewer that is characterized by being lit by a high frequency power source of Hz.