JPS6228635B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a projection television set in which a projector and a screen are separated.

Conventional configuration and its problems The image projected on the phosphor screen of the cathode ray tube is enlarged with a lens, etc., and then projected onto the screen.
Currently, there are two types of projection television equipment: one called a rear type and the other called a front type. In the front type method, the images projected on each of the red, green, and blue cathode ray tubes are enlarged using a lens, etc., and then enlarged and projected onto a screen located in front of the cathode ray tube. The enlarged image of the screen is viewed from the direction in which the projector including the screen is located.

Among these, there is also a type in which the screen and projector are separated. Figure 1 shows the configuration of a projection television set called a separate front system. This includes lenses, etc. A screen 2 separated from the projector 1 is installed in front of the projector 1. Viewer 3 is in front of this screen 2,
That is, the enlarged image on the screen 2 is viewed from the direction in which the projector 1 is located. In this case, the projector 1 is generally short, and therefore, for example, the viewer 3's line of sight 5 when sitting on the chair 4
Considering this, the inclination α ₁ of the optical axis 6 from the projector 1 with respect to this line of sight 5 becomes large. Therefore, the screen 2 is required to have a somewhat inclined projection surface.

In FIG. 1, 7 is a caster that movably supports the projector 1, and 8 is a support that supports the screen 2.

In the above device, it would be difficult to use a flat screen instead of the curved screen shown in the figure because the angle of incidence of the optical axis on the screen would become large, resulting in large deflection distortions such as keystone distortion. . That is, the amount of movement of peripheral images between the two screens increases, causing trapezoidal distortion and other focus blurring, making it difficult to use both screens together. In addition, when using a curved screen and a flat screen together, trapezoidal distortion, which occurs due to the difference in the angle of incidence, and horizontal/
Problems such as vertical linearity distortion and misconvergence may require complicated adjustments for general users, which also makes it difficult to use both screens together.

Purpose of the Invention In view of the above-mentioned conventional problems, the present invention has a projector configured in a vertically elongated manner so that the angle of incidence of the optical axis on the screen is small so that both screens can be used together, and various distortions can be easily controlled. An object of the present invention is to provide a projection type television equipment that can perform corrections.

Structure of the Invention In the present invention, the height of the projector is increased to reduce the angle of incidence on the optical axis from the projector to the screen, and the problems of trapezoidal distortion, misconvergence, and horizontal/vertical linearity distortion are flattened. An adjustment circuit for when a screen is used and an adjustment circuit for when a curved screen is used are provided, and by switching between the two circuits with a switch, it is possible to use two types of screens.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 to 8. In FIGS. 2 to 4, 10 is a projector that includes red, green, and blue cathode ray tubes 11 installed vertically, a magnifying lens 12, and an image transmitted through the magnifying lens 12. It has a built-in mirror 13 that reflects the light toward the screen.
Reference numeral 14 denotes a viewer sitting on a chair 15, and the angle of incidence of the optical axis 17 entering the screen from the cathode ray tube 11 with respect to the viewer's line of sight 16 is _α2 , and _α2 < _α1 .

In this way, the cathode ray tube 11 is arranged vertically to increase the height of the projector 10, and first, the incident angle _α2 is reduced. Therefore, the amount of correction for various distortions between the case where the flat screen 18 is used as the screen and the case where the semi-curved screen 19 having a curved surface only in the vertical direction is used can be reduced accordingly, making it practical.

Figures 5, 6, and 7 show a convergence adjustment circuit and a trapezoidal distortion correction adjustment circuit to enable the use of both semi-curved screens with curved surfaces only in the vertical direction and flat screens. , respectively show linearity correction adjustment circuits. In FIG. 5, 20, 21,
22, 23, 24, 25, 26, 27 are variable resistors for convergence adjustment; 28, 29 are output circuits for convergence correction; 30, 31 are convergence yokes for blue horizontal and red horizontal convergence yokes; 32, 33, 34, 35
They are configured to be interlocked with each other using a changeover switch.

In the convergence adjustment circuit for horizontal blue color, the movable terminal of the variable resistor 20 is connected to one fixed terminal a of the changeover switch 32, the movable terminal of the variable resistor 21 is connected to the other fixed terminal b, and the changeover switch 3
The movable terminal of the variable resistor 22 is connected to one fixed terminal a of the switch 3, and the movable terminal of the variable resistor 23 is connected to the other fixed terminal b of the changeover switch 32.
A vertical sawtooth wave signal is applied to the common terminal of the switch 33, and a parabolic wave with a vertical period is applied to the common terminal of the changeover switch 33. On the other hand, in the red horizontal convergence adjustment circuit, the movable terminal of the variable resistor 24 is connected to one fixed terminal a of the changeover switch 34 to which the vertical sawtooth signal is applied to the common terminal, and the variable resistor 25 is connected to the other fixed terminal b. A variable resistor 26 is connected to one fixed terminal a of the changeover switch 35, which applies a vertically periodic parabolic wave to the common terminal.
Connect the movable terminal of variable resistor 2 to the other fixed terminal b.
7 movable terminals are connected to each other.

FIG. 6 shows a trapezoidal correction adjustment circuit, in which a variable resistor 37 is connected to the collector of a transistor 36 whose collector output terminal shows a vertical sawtooth wave, and a second variable resistor 38 is provided. The variable resistor 38 is connected in parallel to the variable resistor 37 by a switch 39, and the connection thereof is canceled.

FIG. 7 shows a vertical linearity correction adjustment circuit, which includes first and second variable resistors 40 and 41, and which is operated by a switch 42 to adjust the first variable resistor 40, 41.
0, the second variable resistor 41 is connected in parallel or disconnected from the second variable resistor 41.

Here, switches 32, 33, 34, 35, 3
9 and 42 have a switch configuration in which all six circuits and two contacts are interlocked.

Figure 8 shows misconvergence a, b, vertical linearity distortion c, and trapezoidal distortion d when switching from a flat screen to a semi-curved screen. In particular, Figure 8 a shows vertical line orthogonality correction,
Figure b shows misconvergence in vertical line curvature correction.

First, regarding the issue of misconvergence,
Basically, when a semi-curved screen is used, misconvergence occurs regarding the orthogonality of vertical lines and the curvature of vertical lines, as shown in FIGS. 8a and 8b. Therefore, during production, switches 32 to 35 are moved to terminal a side (flat screen side) and convergence adjustment is performed using variable resistors 20, 22, 24, and 26, and then switches 32 to 35 are moved to terminal b side (semi-curved screen side). screen side) and again.
This time, convergence adjustment is performed using variable resistors 21, 23, 25, and 27. Therefore, a general user can obtain an image whose convergence has been adjusted according to the flat screen or semi-curved screen by simply switching the switches 32 to 35. For example, in the case of a semi-curved screen, images with misconvergence corrected as shown in FIG.
35 can be obtained by simply flipping it to the terminal b side.

Regarding the trapezoidal correction adjustment circuit shown in FIG. 6, the switch 39 is moved to the terminal a side (flat screen side) to perform adjustment according to the flat screen using the variable resistor 37, and the switch 39 is moved to the terminal b side (curved screen side). Adjustment according to the curved screen is performed using the variable resistor 38. Therefore, general viewers can adjust trapezoidal distortion by simply switching this switch 42.
For example, it is possible to eliminate the distortion shown in FIG. 8d when a semi-curved screen is used. Similarly, the seventh
Also in the vertical linearity correction adjustment circuit shown in the figure, the switch 42 is set to the terminal a side to perform correction corresponding to the flat screen.
Set it to the terminal b side and perform correction corresponding to the curved screen. All that is left to do is to turn the switch 42.

With this configuration, switches 32 to 35, 39,
It is only necessary to switch 42 with one knob,
Both flat and semi-curved screens can be used.

In FIGS. 3 and 4, 50 is a cabinet constituting the projector, 51 is a speaker, 52 is a side plate for fixing the chassis, 53 is an operation panel, 54 is a terminal board, and 55 is a handle.

Effects of the Invention As described above, according to the present invention, both a semi-curved screen and a flat screen can be used for one type of projector, and distortions corresponding to each screen can be corrected by simply switching a switch. be able to.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a schematic configuration of a conventional projection television device, FIG. 2 is a side view showing a configuration of a projection television device according to an embodiment of the present invention, FIGS. 3 and 4. are a side sectional view and a front view of the projector in the same configuration, FIGS. 5 and 6,
Fig. 7 is a circuit diagram of a convergence correction adjustment circuit, a trapezoidal distortion correction adjustment circuit, and a vertical linearity correction adjustment circuit used in the same installation, and Fig. 8 a, b, c, and d are circuit diagrams for adjusting misconvergence and various distortions. FIG. 3 is a front view of the displayed screen. 10...Projector, 11...Cathode ray tube, 12...
Enlargement lens, 13...Reflection mirror, 18...
...Flat screen, 19... Semi-curved screen, 20-27... Variable resistor for convergence adjustment, 30, 31... Convergence yoke, 32-35, 39, 42... Changeover switch,
37, 38... variable resistor for trapezoidal distortion correction, 40,
41...Variable resistor for vertical linearity correction.

Claims (1)

[Claims] 1. A projector equipped with a means for enlarging the image of a cathode ray tube and projecting it onto a screen in front of the screen, and at least a flat screen adjustment circuit for convergence correction, trapezoidal distortion correction, and vertical linearity correction, and a semi-semi having a curved surface in the vertical direction. 1. A projection television apparatus, wherein adjustment circuits for curved screens are provided independently, and the adjustment circuits are switched by a changeover switch depending on the screen used.