JPS603536A - Projection test equipment - Google Patents

Abstract

PURPOSE:To execute a setting of a lens with high reproducibility, and to improve an objectivity of projection test and also operability by executing a setting of a lens by using an output signal of an image pickup element. CONSTITUTION:A titled device is constituted of a light source 7, a test chart 8 having a stripe pattern consisting of a dark part and a bright part at a position shown by a circle 9, a lens 10, a screen 11, and one-dimensional image pickup elements 12, 12' and 13, 13' provided on the screen 11. In addition, this device is provided with differentiating and peak holding circuits 14, 14' for differentiating an output signal of each one-dimensional image pickup element, and holding its peak value, and a comparing circuit 15 for comparing the outputs of the corresponding one-dimensional image pickup elements of the upper and lower parts, and the left and right. Setting of a lens is adjusted so that the output of the comparing circuit 15 becomes zero. The differentiating circuit is used for deriving easily a contrast from the output signal of each one-dimensional image pickup element, and omitted in case when the setting of a lens is executed by an intensity of an image.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for projection testing a lens for a projection television receiver.

Conventional configurations and their problems Lenses for projection television receivers often have standard mounts similar to those for camera lenses, and lens setting during projection tests is unclear. Moreover, the determination of the tilt of the lens is carried out by projecting resolution charts 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 2, 3, 3, 3, 4, 5, 4, 5, 4, 5, 6, 5, 5, 5, 5, 4, 5, , , , , , , , , , , , , , , , , , , , , , , , bal anced images of resolving power on a screen.

However, the above method is basically a sensory method and has large individual differences, and the determination amount is strictly defined, making it difficult to obtain reproducibility.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned drawbacks of the prior art and provides a power projection testing device that allows lens setting to be performed with good reproducibility using an image pickup device.

Structure of the Invention The present invention relates to a projection test device consisting of a light source, a test chart, a lens for a projection type television to be tested (hereinafter simply referred to as a lens), and a screen, in which four locations are placed on the screen at four locations on the top, bottom, left and right at an appropriate angle of view. A one-dimensional image sensor is placed in the image sensor, and these positions are determined so that an image of the bright and dark striped pattern on the corresponding test chart appears on each one-dimensional image sensor. As shown in FIG. 1, the striped patterns 1 and 2 are arranged so that the projected images on the screen cross a one-dimensional image sensor 3. With this configuration, the output signal of each one-dimensional image sensor is modified to the light and shade of the striped pattern image as shown in FIG. 2, and the output signal changes depending on the setting of the lens. If the lens settings are perfect, the output signals of the three-dimensional image sensors arranged vertically, horizontally, and vertically will be equal. It also utilizes the principle that if there is a tilt in the lens setting, an imbalance will occur in the outputs of a pair of one-dimensional imaging elements arranged in the direction of the tilt.

Description of examples Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 3, this projection test apparatus has a test chart 8. having a striped pattern consisting of the dark area 1 and bright area 2 of FIG. Lens 10. A screen 11, and a one-dimensional image sensor 12.12' on the screen 11 as shown in FIG.

13.13'. However, for convenience of explanation, only two of the four one-dimensional image sensors are shown in FIG. 3 as a pair. In addition, there are differentiation/peak hold circuits 14 and 14' for differentiating the output signal of each one-dimensional image sensor and holding its peak value, and a comparison circuit 16 for comparing the outputs of the corresponding one-dimensional image sensors on the upper, lower, left and right sides. will be established.

Note that FIG. 4 shows a case where a tilt occurs in the lens setting.

Next, the operation of this embodiment will be explained. The light and dark striped pattern on the test chart has a rectangular wave-like contrast as shown in Figure 6 (a), but the image on the screen has a contrast as shown in Figure 5 (b), and the output of the -dimensional image sensor The signal also comes on. When this signal waveform is differentiated, Figure 5 (
A signal like o) is obtained. These signal waveforms change depending on the lens setting; for example,
In the case where the lens setting is tilted as shown in the figure, the -dimensional image sensor 12 is
The -dimensional image pickup device 12' generates six output signals as shown in FIG. 5(d). The differential waveforms of both signals jump as shown at (0) and tel+ in FIG. 5, respectively. After the peak hold, the output of the comparison circuit is clearly higher than the output of the one-dimensional image sensor 12' than the one-dimensional image sensor 12'. represents something.

The lens setting is adjusted so that the output of the comparator circuit 16 is zero.

The differentiating circuit is used to simply calculate the contrast from the output signal of each dimensional image sensor, and is omitted when setting the lens according to the intensity of the image.

Effects of the Invention As described above, the present invention uses the output signal of the image sensor to set the lens when testing a lens for a projection television receiver, and is therefore more effective than the conventional sensory method. It is possible to set the lens with much higher reproducibility, which greatly helps improve the objectivity of projection tests and, by extension, work efficiency.

[Brief explanation of drawings]

Figure 1 shows the test chamber 6 on the light receiving part of the one-dimensional image sensor.
- A diagram showing the positional relationship with a single striped pattern image, Figure 2 is a layout diagram of each -dimensional image sensor on the screen of the projection test device, and Figure 3 is a schematic configuration of an embodiment of the present invention. 4 are state diagrams in the case where a tilt occurs in the lens setting in the same embodiment, and FIG. 5 is a signal waveform diagram of each part of FIG. 3. 7...Light source, 8...Test chart,
1o... Lens for test projection type television receiver, 11...-Screen, 12, 12',
13, 13'...-dimensional image sensor, 14,
14'...Differential/peak hold circuit, 15.
...Comparison circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A test chart having a bright and dark striped pattern at symmetrical positions vertically and horizontally, and a one-dimensional imaging device arranged on a screen corresponding to the projected image position of the striped pattern are provided, and a one-dimensional imaging device of the test chart image is provided. A projection test device characterized in that a lens to be tested is set based on an output signal.