JPH01105989A - Active screen - Google Patents

Abstract

PURPOSE: To project a sharp image even in a light place by photodetecting an image projected on a screen by a light receiving element and connecting a light emitting element so that light is emitted according to the quantity of received light. CONSTITUTION: The screen 1 consists of photodiodes PD4. light emitting diodes LD6, and circuit units 5 arrayed in quantities on a ceramic substrate 2 and a display surface in matrix. The units 5 connect the PDs 4 and LDs 6, and the current gains of the PDs 4 are amplified by amplifiers to drive the LDs 6. Therefore, the LDs 6 illuminate higher luminance in proportion to the quantities of light made incident on the PDs 4. A projector 8 which projects the image on the surface 3 is equipped with a chopper disk 10 having a slit and the disk rotates at a constant speed to project the image on the surface 3 intermittently at a specific frequency. The units 5 includes filter circuits which cut DC components, so the influence of external light can be removed, so the sharp image can be projected even in a light place.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a light-receiving element to receive an image projected on a screen by a projector, etc., and a light-emitting element that emits light according to the intensity of the received light, thereby producing a bright and clear image. This invention relates to an active type screen (hereinafter referred to as an active screen) that projects an image.

[Conventional technology]

A screen is used when displaying images using a projector. A conventional screen is made by coating the surface of a sheet such as a canvas with a white paint that is highly scattering and reflective.

The image from the projector that is projected onto the surface of the screen is observed by scattering and reflection.

[Problem that the invention seeks to solve]

However, with the conventional screens mentioned above, the brightness of the image displayed on the screen is controlled by the light source lamp of the projector, so they have the disadvantage that they cannot display clear and bright images when used in bright places. be.

The present invention has been made to solve the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide an active screen that can display clear and bright images even when used in a bright place.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention includes a large number of light-receiving elements for each pixel to receive an image formed by stepped light from a projector, and a circuit unit and a circuit unit provided corresponding to each of the light-receiving elements. A light emitting element and the light receiving element 2
A light-emitting screen is constructed from a circuit unit and a substrate on which light-emitting elements are arranged and held.

[Effect]

According to the above configuration, the image is received pixel by pixel by a large number of light receiving elements. The photoelectric output for each pixel output from each light receiving element is inputted to the corresponding light emitting element through each circuit unit, and self-luminous image display is performed by driving these light emitting elements. become.

〔Example〕

As shown in FIG. 1, a screen 1 using the present invention includes a ceramic substrate 2, and a large number of photodiodes 42 arranged in a matrix on one surface (display surface) 3 of the substrate 2, a circuit unit 52, a light emitting diode 6, It consists of. The circuit unit 5 connects the photodiode 4 and the light emitting diode 6 as shown in FIG. 2, and amplifies the current gain of the photodiode 4 with a transistor T1, thereby driving the light emitting diode 6. Therefore, the light emitting diode 6 is illuminated at a brightness proportional to the amount of light incident on the photodiode 4 and higher than the amount of light incident on the photodiode 4. Such a circuit unit 5 can be formed, for example, by a thin film process, and can also have a layered structure located below the photodiode 4 or the light emitting diode 6.

In addition, as the circuit unit 5, as shown in FIG. 3, transistors T2. If a combination of amplifier circuits consisting of T3 is used, the current gain can be further increased.

As shown in an enlarged view in FIG. 4, the photodiode 4 includes photodiodes 4B and 4G arranged separately for each color.
, 4R, and in front of them are arranged a blue filter B, a green filter G, and a red filter R that selectively transmit blue, green, and red, respectively, and these constitute a light receiving section for one pixel. Ru. Moreover, the light emitting diode 6 is
A light emitting diode 6B for blue light emission and a light emitting diode 6G for green light emission correspond to the filters B, G, and R.

It is composed of a light emitting diode 6R for emitting red light, and these serve as a light emitting section for one pixel.

In addition, the respective photodiodes 4B and 4G.

Between 4R and the light emitting diodes 6B, 6G, and 6R, there is a light shielding band 7 that protrudes further toward the front of the screen than these elements.
is provided, and a light emitting diode 6B.

The light from 6G and 6R is transmitted to each photodiode 4B and 4.
It is designed so that it will not be directly incident on G and 4R. Such a light-shielding band 7 can be produced, for example, by screen printing black resin on the substrate 2 or by etching a photoresist.

Furthermore, when the screen size is large such as 2m x 3m, a pixel size of about 1 to 2mm is preferable, and when the screen size is 1m x 1m or less,
A pixel size of about 100 μm to 200 μm is preferable.

As shown in FIG. 1, an image is projected onto the display surface 3 of the bright room type screen 1 configured as described above using the projector 8. This projector 8 is equipped with a chopper disk 10 that is rotated at a constant speed by a motor and has slits formed in the disk, and an image is intermittently projected onto the display surface 3 by the chopper disk 10 at a predetermined frequency. It becomes like this. Since the circuit unit 5 incorporates a filter circuit for canting the direct current component, by intermittent the projected image in this way, it becomes possible to remove the shadow of external light. Note that it is also possible to use a liquid crystal shutter or the like as a means for intermittent projection images at a predetermined frequency.

Each of the photodiodes 4B, 4G, and 4R outputs a photoelectric signal corresponding to the brightness and darkness of the projected image pattern. This photoelectric signal is transmitted to photodiodes 4B, 4G, 4
The signal is amplified by the circuit units 5B, 5G, and 5R provided for each R, and is used as a drive signal for the light emitting diodes 6B, 6G, and 6R. Therefore, the light emitting diodes 6B, 6
G, 6R are the corresponding photodiodes 4B, 4G, 4
Since it is turned on with an amount of light emitted proportional to the amount of incident light of R, the projected image from the projector 8 is displayed on the display surface 3. Further, the intermittent frequency of the image projected by the chopper disk 10 is a frequency that is not noticeable to the naked eye and does not match the flicker of a fluorescent lamp (for example, 65 to 85 Hz).
, 40-45 Hz).

Note that in the above embodiment, the light emitting diode 6B is used.

A light shielding band 7 is used to prevent the light from 6G and 6R from directly entering the photodiode 4, but even if the photodiode 4 is buried in a recess formed in the substrate 3 as shown in FIG. A similar effect can be obtained.

FIG. 6 shows another embodiment of the invention. In this embodiment, one side of the substrate 11 is used as an image receiving surface 12. The other surface is used as the display surface 13. For this reason, photodiodes 4B, 4G, and 4R are arranged in a matrix along with filters B, G, and R on the image receiving surface 12.
3, light emitting diodes 6B, 6G, and 6R are arranged in a matrix in correspondence with the arrangement of the photodiodes 4B, 4G, and 4R. Furthermore, a pore 14 is formed in the substrate 11, and the photodiodes 4B, 4G, 4R are connected to the circuit units 5B, 5G, 5R through this pore 14.

According to this embodiment, images can be projected by the projector 8 from the back side of the display surface 13.

Note that if the connections between the photodiodes 4B, 4G, and 4R and the light emitting diodes 6B, 6G, and 6R are properly aligned, it is possible to prevent the image on the display surface 13 from being blinded to the image projected from the projector 8. can.

Furthermore, as shown in FIG. 7, by densely arranging the photodiodes 4 on the image receiving surface 12 side with respect to the arrangement of the light emitting diodes 6, it is also possible to enlarge and display the image projected by the projector 8. It is. The dense array of photodiodes 4 may be provided on the display surface 13 so as not to interfere with the array of light emitting diodes 6. In addition, in the embodiment described above, filters B, G, R
By omitting , it is also possible to display in monochrome.

Note that the present invention can be used not only as a screen for a projector in a bright room or outdoors, but also as a screen for a finder of a camera, for example. In this case, the object image may be formed on one surface of the active screen by the finder optical system, and framing and focusing may be performed based on the image of the object displayed on the other surface of the active screen.

〔Effect of the invention〕

As described above, according to the active screen of the present invention, the light receiving element receives the image projected on the screen, and the light emitting element is connected so as to emit light with an amount of light corresponding to the amount of received light. Therefore, by causing the light-emitting element to emit light with an amount of light greater than the amount of light received by the light-receiving element, it is possible to project a clear image on the screen even in a bright place. In addition, since it is easy to separate the light receiving means and the light emitting means, it is possible to make the image projected on the back of the screen clearer and display it on the surface that the viewer sees, and by arranging the light receiving element in a small section, it is possible to It is also possible to project an enlarged image of the image projected onto the screen, which is extremely convenient in practice.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of the present invention. FIG. 2 is a circuit diagram showing an example of a circuit configuration used in the present invention. FIG. 3 is a circuit diagram showing another example of the circuit configuration. FIG. 4 is a partially enlarged perspective view of the embodiment shown in FIG. 1. FIG. 5 is a partial sectional view showing another embodiment of the present invention. FIG. 6 is a partial sectional view showing still another embodiment of the present invention. FIG. 7 is a partial sectional view showing an embodiment of the present invention for displaying an enlarged image. 2...Substrate 4...Photodiode 5...Circuit unit 6...Light emitting diode 7...Shading band 8...Projector.

Claims (7)

[Claims] (1) A large number of light-receiving elements are arranged on a substrate to receive the formed image pixel by pixel, and photoelectrons are arranged on the substrate in correspondence with the arrangement of these light-receiving elements, and photoelectrons from each light-receiving element are An active screen characterized by comprising a plurality of light emitting elements whose lighting is controlled in proportion to output. (2) The active screen according to claim 1, wherein the light receiving element and the light emitting element are each arranged in a matrix on one surface of the substrate. (3) The active screen according to claim 2, wherein a light-shielding wall is provided between the light emitting element and the light receiving element. (4) The active screen according to claim 2, wherein the light receiving element is embedded in a recess formed in the substrate. (5) The active screen according to claim 1, wherein the light receiving elements are arranged in a matrix on one side of the substrate, and the light emitting elements are arranged in a matrix on the other side of the substrate. (6) The active screen according to claim 5, wherein the substrate is provided with pores through which wiring electrically connects the light receiving element and the light emitting element. (7) The arrangement area of the light receiving elements is separated from the arrangement area of the light emitting elements, and the arrangement of the light receiving elements is made denser than the arrangement of the light emitting elements.
5. The active screen according to any one of paragraphs 1 and 5.