JP3899641B2 - Reflective projector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reflection type projector using a reflection type display device, and particularly relates to a reflection type projector using a rotating color filter.
[0002]
[Prior art]
The reflection type projector according to the prior art shown in FIG. 6 condenses white light from a white light source L such as a metal halide lamp with a first condenser lens Ln1, and uses color filters such as RGB arranged in a minimum condensing area area. The light beam selectively transmitted through the rotating color filter 1 is projected onto the reflective display device 4 by the second condenser lens Ln2, and the reflected light modulated by the video signal is projected onto the screen S by the projection lens Ln3. The reflective display device 4 is formed of a liquid crystal panel or the like in which a total reflection film is formed on the back side of the incident light surface, and the switch transistor for each pixel is formed inside the reflection film, so that the aperture ratio of the liquid crystal panel is high. There are provided inexpensive devices that can use a monochrome liquid crystal panel without a color filter or the like and do not need to use a dichroic mirror or a dichroic prism. However, the RGB rotating color filter rotates at a speed of one rotation per frame or field, and when the user of the projector blinks or moves his / her head, the screen projected and output on the screen is unnatural. Problems that you can see or feel flickering occur.
[0003]
[Problems to be solved by the invention]
In view of the above problems, an object of the present invention is to provide a reflection type projector using a rotary color filter of a type in which a screen projected and output on a screen looks natural and does not feel flicker.
[0004]
[Means for Solving the Problems]
White light from a white light source such as a metal haloid lamp is condensed by the first condenser lens, and the light that has been color-selected and transmitted by the rotating color filter placed in the minimum condensing area is reflected by the second condenser lens. In a reflective projector that projects on a device and reflects the light modulated by the video signal onto the screen with a projection lens,
A rotating color filter through which a color filter having the same color selection characteristic passes a plurality of times in one field period of a video signal, a motor for rotating the rotating color filter, and a sensor for detecting an index representing the rotating phase of the rotating color filter; Image storage means for cyclically storing video signals as n-bit color-specific digital image data, means for generating timing pulses from the rotational phase detected by the sensor, and digital image data are read in order of color and level by timing pulses The display control device includes a means for driving the reflective display device and a means for controlling the rotation color filter in synchronization with the video signal.
[0005]
In addition, the rotation color filter
A color filter having an angle proportional to the level weight of the bit of the digital image data for each color is formed, and n color filters of the same bit for each color are alternately arranged in the bit weight order.
A color filter having an angle proportional to the level weight of the bit of the digital image data for each color is formed, and n color filters having the same bit for each color are alternately arranged in an arbitrary order.
Forming a color filter of an angle proportional to the minimum level weight of the bit of the digital image data by color, and alternately arranging the color filters of each color;
Alternatively, color filters having the same angle are formed.
[0006]
In addition, the color filter
Use primary color filters such as R (red), G (green), and B (blue).
Alternatively, color difference color filters such as RY and BY are used.
[0007]
In addition, the index
It is composed of VBL representing a vertical synchronization unit, BL representing the bit boundary, CL representing the color boundary, and the like.
In addition, the index
Formed with black stripes formed on a rotating disk,
Formed with a cord pattern formed on a rotating disk,
A through-hole formed on the rotating disk,
Alternatively, a magnetic film or a magnet is formed on the rotating disk.
[0008]
In addition, reflective display devices
A ferroelectric liquid crystal device having a reflection surface for all colors;
Alternatively, a DMD that performs electrostriction control on all color reflecting surfaces is used.
[0009]
Furthermore, the display control device
A / D for converting an analog video signal into digital image data, an image memory for storing one field or frame of digital image data, a selector for selectively storing digital image data in each field or frame, and selecting and storing in the image memory An image is obtained from an amplifier that amplifies the index signal detected by the sensor, a timing decoder that generates a timing signal such as VBL, BL, and CL from the index signal, a video synchronization signal, and a timing pulse such as VBL, BL, and CL. Reads the image data from the data memory, generates a timing pulse for conversion to a predetermined image data array, reads the parallel image data from the image data memory based on the timing pulse, a gradation control unit for controlling the gradation of the image, Image data for each level A data selector for selecting and outputting the data, an X register for performing data transfer driving in the X direction of the reflective display device, a Y drive for performing data transfer driving in the Y direction of the reflective display device using the selected output image data, The drive control unit controls the rotation of the motor by the timing signal and the video synchronization signal, and the drive unit drives the motor power supply by the output of the drive control unit.
[0010]
In addition, the data selector
Consists of a multiplexer that arbitrarily selects a plurality of input data, and selectively outputs image data of a predetermined color bit by a timing pulse.
Alternatively, an AND gate that performs a logical product with a timing pulse for each color bit and an OR gate that performs a logical sum with all the AND gate outputs are configured.
[0011]
Furthermore, the timing pulse generated by the gradation control unit is
The pulse has a pulse width proportional to the bit weight for each color.
Alternatively, it is a pulse having a pulse width proportional to the minimum bit weight, and is repeatedly output n times for each color.
[0012]
In addition, the sensor
A photodiode,
Phototransistor
Alternatively, a magnetic sensor such as a magnetic head or a magnetoresistive device is used.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram of a main part of an embodiment of a reflective projector according to the present invention, FIG. 2 is a block diagram of various embodiments of a rotating color filter according to the present invention, and FIG. FIG. FIG. 4 is an explanatory diagram showing the configuration of the color filter of the present invention, and FIG. 5 is a control timing chart of the data selector and timing pulse according to the present invention.
The general operation of the projector will be described with reference to FIG.
This apparatus is a reflective projector having a display capability of 4,000 colors, in which R (red), G (green), and B (blue) analog signals of a VGA (640 dots × 480 lines) screen are input from a computer. Therefore, display control is performed for each RGB color based on 4-bit image data.
The apparatus condenses white light from a white light source L such as a metal haloid lamp by a first condenser lens Ln1, and is arranged in a condensing minimum area portion, and has the same color selection characteristic in one field period of a video signal. A light beam selectively transmitted through the rotating color filter 2 through which the color filter passes a plurality of times is projected onto the reflective display device 4 by the second condenser lens Ln2, and the reflected light modulated by the video signal is projected onto the screen S by the projection lens Ln3. It is a reflection type projector that projects on the screen. The rotary color filter 2 is driven to rotate by the motor 2, and an index representing the rotation phase is detected by the sensor 3.
[0014]
The reflective display device 4 has an optical switch type characteristic in which the reflectance is controlled to 1 or 0 by a drive input signal, and the brightness of the reflected light depends on the ON / OFF time ratio of the optical switch and the afterimage phenomenon of the human eye. Is expressed as an average luminance per unit time (30 to 60 milliseconds). The reflective display device 4 employed by this apparatus is a ferroelectric liquid crystal device having an all-color reflecting surface, or a DMD that controls electrostriction of the all-color reflecting surface.
The display control device 5 includes an image storage means for cyclically storing 4-bit color-specific digital image data after analog / digital conversion of the RGB analog signal of the VGA screen input from the video input terminal 6, and the sensor 3. Means for generating a timing pulse from the rotational phase detected in Step 1, means for driving the reflective display device 4 by reading out digital image data in order of color and level in accordance with the timing pulse, and rotational control for synchronizing the rotational color filter 1 with the video signal. Means for performing. Further, the rotational color filter 1 driven to rotate by the motor 2 is controlled to rotate in synchronization with the input video signal, and a timing pulse is generated from the index detected by the sensor 3, and stored in the image storage means by the timing pulse. The digital image data is read out in order of color and level, and the reflective display device 4 is driven.
[0015]
Various rotating color filters will be described with reference to FIG.
(A) is a first embodiment, in which a color filter film of RGB primary colors is formed on a rotating disk. The rotating disk rotates once in one field period of the image, and the color filter film is formed corresponding to the image data bit of each color. r8 and r1 are color filters for the most significant bit of R (hereinafter referred to as MSB) and the least significant bit of R (LSB). The color filter formation angle is assigned an angle proportional to the weight (ratio) of the video level of the corresponding bit. r8 is for MSB of 4-bit image data and a ratio of 8 is given, and r1 is for LSB and a ratio of 1 is given. The color filters are r8-g8-b8-r4-b4-b4-. . . . . Arranged in the order of r1-g1-b1 and the vertical blanking period, the black stripe (BL) and the index portion 1a are arranged in a part thereof. Also, BL is arranged at the boundary for each bit, and a thin black stripe (CL) is arranged at the boundary between the colors. For the index portion, a means such as the above-described black stripe, a code pattern such as a barcode, a simple transparent hole, or a magnetic film or a magnet is selected.
[0016]
(B) is a second embodiment, in which 16 sets of RGB primary color filter films having LSB weights are formed on a rotating disk.
(C) is the third embodiment, the RGB primary color filter films are arranged at an equal angle of about 120 degrees, and the rotation speed of the rotating disk rotates at 16 times the speed of the first and second embodiments. Driven.
[0017]
(D) is a fourth embodiment, in which a total reflection film is formed on the mirror-finished surface of a rotating cylinder, and a color filter is disposed on the reflection film at an equal angle of about 120 degrees. is there. The reflected light that has been condensed and selectively reflected by the first condenser lens Ln1 on the outer peripheral surface of the rotary color filter is incident on the reflective display device 4 by the second condenser lens Ln2. The rotating cylinder is driven to rotate by a motor 2, and the index portion is formed of a black stripe, a code pattern, a magnetic film, or the like on a reflective film in the same manner as the color filter. It is cylindrical and suitable for high-speed rotation.
This rotating color filter requires an optical means for correcting geometric distortion of reflected light that is color-selectively reflected on the cylindrical surface, but its description is omitted.
[0018]
In the fifth embodiment (not shown), the color filters of the respective colors are not arranged in order of level weight, but the upper bit and lower bit color filters are alternately arranged in the first embodiment. Generation of flicker or the like can be further suppressed.
[0019]
As the color filter, a primary color filter such as RGB as described above and a color difference filter of a color difference format such as RY and G-Y are used. In the latter color difference filter, the image data configuration and processing form are different.
[0020]
Further, detailed operation of the display control device 5 will be described with reference to FIGS.
The display controller 5 switches the analog image signal to digital image data A / D 61, image memory 63, 64 for storing one field or frame of digital image data, and digital image data for each field or frame. A selector 62 to be selected and stored in the image memory, an amplifier 51 for amplifying an index signal detected by the sensor 3, a timing decoder 52 for generating a timing signal such as the VBL, BL, and CL from the index signal, and video synchronization Gradation for controlling image gradation by reading out image data from the image data memories 63 and 64 from the signal and timing pulses such as VBL, BL, and CL, and generating timing pulses for conversion into a predetermined image data array. Based on the control unit 66 and the timing pulse, A parallel image data is read from the data memory, and a data selector 65 for selectively outputting image data for each color and level, an X register 68 for driving data transfer in the X direction of the reflective display device 4, and an image selected and output A Y drive 67 that performs data transfer driving in the Y direction of the reflective display device with data, a drive control unit 53 that controls the rotation of the motor 2 using the timing signal and the video synchronization signal, and a motor that is output from the drive control unit And a drive unit 54 for driving two supply power sources.
As the sensor 3, a photodiode, a phototransistor, or a magnetic sensor such as a magnetic head or a magnetoresistive device is selected.
[0021]
The RGB analog signals of the VGA screen input from the video input terminal 6 are analog / digital converted by the A / D 61 and are cyclically stored in the image data memories 63 and 64 as 4-bit color-specific digital image data. The selector 62 selects and inputs image data to the image data memory alternately for each field. In the image data memory, the image data is cyclically overwritten and stored on the previously stored data.
The index representing the rotational phase formed on the rotational color filter 1 that is rotationally driven by the motor 2 is detected by the sensor 3, amplified by the amplifier 51, and then VBL representing the vertical synchronization unit by the timing decoder 52 for each bit. A timing signal in which BL representing the boundary of the color, CL representing the color boundary, etc. represents the rotational phase is decoded. On the other hand, the drive control unit 53 inputs a signal obtained by performing phase comparison control between the decoded VBL and the vertical synchronization V separated from the input video signal to the drive unit 54 and performs drive rotation control of the motor 2.
[0022]
FIG. 4A is an explanatory diagram showing the rotational phase of the above-described rotational color filter. The color filters according to the prior art are equally arranged in 1/3 period of one field period so as to be displayed as RGB.
The rotational color filter of the first embodiment is displayed separately for each color such as R, G and B. First, r8 is about 8/48 field periods, then g8 and b8 are similarly about 8/48 filled periods. Subsequently, r4, g4, and b4 are about 8/48 field periods, r2, g2, and b2 are about 2/48 filled periods, and r1, g1, and b1 are about 1/48 filled periods. Here, “about” is because the index part is omitted.
[0023]
FIG. 4 (b) shows a rotating color filter of the second embodiment, in which 16 sets of r1, g1, and b1 are arranged in a combination of about 1/48 filled period.
FIG. 4 (c) shows that the first embodiment is arranged in the order of the video signal bit weights, whereas the color filters for the upper bits and the lower bits are alternately shown as r8-r1-r4-r2. Has been placed.
[0024]
FIG. 5B is a time chart of the index signal and timing pulse of the first embodiment of the rotary color filter. P0 represents an index signal composed of VBL, CL, and BL. Pm is a timing pulse for reading out and displaying LSB image data, and m represents the weight of the video level. P8 (m = 8) is a MSB, and P1 (m = 1) is a timing pulse for reading and displaying LSB image data. Rm means a timing pulse for reading out and displaying R image data. These timing pulses are generated by the gradation control unit.
[0025]
FIG. 5 (a) shows an embodiment of the data selector 65, which is composed of an 8-input 1-output multiplexer 65a. The aforementioned Pm is used as the input selection control signal of the multiplexer 65a. Rm, Gm, and Bm are directly input to the read control terminals of the image data memories 63 and 64, and are used for read control for each color. The image data memory has a parallel output terminal for outputting parallel image data, and the input terminal of the multiplexer 65a is connected to the parallel output terminal. As a result, 1 or 0 of bit data for each color and each video level is obtained from the output of the multiplexer 65a. The bit data for each color and each video level is input to the Y drive 67 and used as a luminance control signal for the reflective display device.
[0026]
FIG. 5 (a) shows another embodiment of the data selector 65. Instead of a multiplexer, eight AND gates that perform logical product of the read image data of the image data memories 63 and 64 and Pm, It is composed of OR gates that perform logical OR of outputs and has equivalent functions.
[0027]
The timing pulse is generated by the second method regardless of the method of generating Pm having a pulse width proportional to the level weight of the video signal described above. When the rotating color filters of the second, third, and fourth embodiments are used, the index signals are only BL and CL, and the cycle of CL is equivalent to LSB (r1, g1, b1). For this reason, instead of the occurrence of P8 (m = 8), the equivalent effect is obtained by scanning the image data read and display repeatedly 8 times in the period of P1, m (m = 8) times.
[0028]
【The invention's effect】
The present invention is implemented in the form described above, and has the following effects.
A rotation color filter in which a color filter having the same color selection characteristic passes a plurality of times in one field period of the video signal is controlled to rotate in synchronization with the input video signal, and generates a timing pulse from the rotation phase detected by the sensor. By reading the digital image data in the order of color and level and driving the reflective display device, it is possible to provide a reflective projector that allows the screen projected and output on the screen to look natural and feels no flicker.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a main part of an embodiment of a reflective projector according to the present invention.
FIG. 2 shows various embodiments of a rotating color filter according to the present invention.
FIG. 3 is a main part block diagram of an embodiment of a display control device according to the present invention;
FIG. 4 is an explanatory diagram showing a configuration of a color filter of the present invention.
FIG. 5 is a control timing chart of a data selector and a timing pulse according to the present invention.
FIG. 6 is a configuration diagram of a main part of a reflection type projector according to the prior art.
[Explanation of symbols]
S Screen L White light source Ln1, Ln2 Condenser lens Ln3 Projection lens 1 Rotating color filter 1d Rotating cylinder 2 Motor 3 Sensor 4 Reflective display device 5 Display controller 51 Amplifier 52 Timing decoder 53 Drive controller 54 Driver 61 A / D
62 Selector 63, 64 Image memory 65 Data selector 65a Multiplexer 66 Gradation controller 67 Y drive 68 X register

Claims (23)

The white light from a white light source such as a metal halide lamp is collected by the first condenser lens, and the light that has been color-selected and transmitted by the rotating color filter placed in the minimum condensing area is reflected on the reflective display device by the second condenser lens. In the reflection type projector that projects the reflected light that is light-modulated with the video signal onto the screen with the projection lens,
A rotating color filter through which a color filter having the same color selection characteristic passes a plurality of times in one field period of the video signal, a motor for rotating the rotating color filter, and a sensor for detecting an index representing a rotating phase of the rotating color filter Image storage means for cyclically storing the video signal as n-bit digital image data by color, means for generating a timing pulse from the rotational phase detected by the sensor, and the digital image data in color order by the timing pulse. A display control device comprising: means for reading out the reflective display device in order of level; and means for controlling the rotation color filter in synchronization with the video signal.
The rotation color filter is controlled to rotate in synchronization with an input video signal, generates a timing pulse from the rotation phase detected by the sensor, reads the digital image data in order of color and level by the timing pulse, and the reflection type display A reflection type projector that drives a device. The rotating color filter;
2. A color filter having an angle proportional to a level weight of a bit of digital image data for each color is formed, and n color filters having the same bit for each color are arranged alternately in the bit weight order. The reflective projector described. The rotating color filter;
2. A color filter having an angle proportional to a level weight of a bit of digital image data for each color is formed, and n color filters having the same bit for each color are alternately arranged in an arbitrary order. Reflective projector. The rotating color filter;
2. The reflection type projector according to claim 1, wherein a color filter having an angle proportional to the minimum level weight of the bit of the digital image data for each color is formed, and the color filters for each color are alternately arranged. The rotating color filter;
The reflective projector according to claim 1, wherein color filters having equal angles are formed. The rotating color filter;
2. The reflection type projector according to claim 1, wherein the reflection type rotation cylindrical color filter is formed by forming color filters of equal angles on the reflection film. The color filter,
The reflective projector according to claim 3, wherein the reflective projector is a primary color filter such as R (red), G (green), and B (blue). The color filter,
7. The reflective projector according to claim 3, wherein the color difference color filter is RY (luminance signal), BY, or the like. The index
2. The reflection type projector according to claim 1, comprising a VBL representing a vertical synchronizing unit, a BL representing a boundary between the bits, a CL representing a color boundary, and the like. The index
The reflective projector according to claim 9, wherein the reflective projector is formed of a black stripe formed on a rotating disk. The index
The reflective projector according to claim 9, wherein the reflective projector is formed of a code pattern formed on a rotating disk. The index
The reflective projector according to claim 9, wherein the reflective projector is a through hole formed on the rotating disk. The index
10. The reflection type projector according to claim 9, wherein the reflection type projector is formed of a magnetic film or a magnet on the rotating disk. The reflective display device,
2. A reflective projector according to claim 1, wherein the liquid crystal device is a ferroelectric liquid crystal device having a reflection surface for all colors. The reflective display device,
2. The reflection type projector according to claim 1, wherein all the color reflection surfaces are DMD (Digital Mirror Divice) for electrostriction control. The display control device;
An A / D (Analog Digital Converter) for converting an analog video signal into digital image data, an image memory for storing one field or frame of the digital image data, and switching the digital image data for each field or frame A selector for selecting and storing in the memory; an amplifier for amplifying the index signal detected by the sensor; a timing decoder for generating a timing signal such as the VBL, BL, and CL from the index signal; the video synchronization signal and the VBL , BL, CL, etc., a gradation control unit that reads out image data from the image data memory, generates a timing pulse for conversion into a predetermined image data array, and controls gradation of the image; and the timing Based on the pulse, the image data The parallel image data is read from the data, and the data selector for selectively outputting the image data for each color and level, the X register for driving the data transfer in the X direction of the reflective display device, and the image data selected and output Y drive for driving data transfer in the Y direction of the reflective display device, a drive control unit for controlling rotation of the motor by the timing signal and the video synchronization signal, and an output of the drive control unit for the motor The reflection type projector according to claim 1, comprising: a drive unit that drives the power supply. The data selector,
17. The reflection type projector according to claim 16, comprising a multiplexer that arbitrarily selects a plurality of input data, and selectively outputting image data of a predetermined color bit by the timing pulse. The data selector,
2. An AND gate that performs a logical product with a timing pulse for each color bit, and an OR gate that performs a logical sum with the output of all the AND gates, and selectively outputs image data of a predetermined color bit. 16. The reflection type projector according to 16. The timing pulse generated by the gradation control unit is
17. The reflection type projector according to claim 16, wherein the pulse has a pulse width proportional to the bit weight for each color. The timing pulse generated by the gradation control unit is
17. The reflection type projector according to claim 16, wherein a pulse having a pulse width proportional to the minimum bit weight is output repeatedly for every nth power of 2 for each color. The reflective projector according to claim 1, wherein the sensor is a photodiode. The reflective projector according to claim 1, wherein the sensor is a phototransistor. The reflective projector according to claim 1, wherein the sensor is a magnetic sensor such as a magnetic head or a magnetoresistive device.

Images