KR101562261B1 - Projection apparatus, projection method, and storage medium having program stored thereon, which provide high-quality image by effectively using spoke period - Google Patents

Abstract

According to the present invention, there is provided a projection apparatus comprising: a light source section for circularly emitting light of a plurality of colors by time division; A display element which uses light from the light source, displays an image corresponding to a color component of the light, and forms an optical image by the reflected or transmitted light; A projection unit for projecting the optical image formed by the display element toward a projection target; A spoke setting means for setting a switching timing of the light of the plurality of colors and a spoke period around the switching timing; A light source driving means for driving the light source section based on the switching timing and the spoke period set by the spoke setting means; Detection means for detecting information indicating the amount of light for each color light emitted from the projection unit during the spoke period; And a light source control means for controlling the light source so as to maintain the color balance of the color mixture in the spoke period at a desired balance based on the information indicating the amount of light for each color light obtained by the detection means .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection apparatus, a projection method, and a storage medium storing a program for effectively utilizing a spoke period to provide a high-quality image. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a projection apparatus, PERIOD}

The present invention relates to a projection apparatus capable of adjusting a difference in color balance occurring during a spoke period, a projection method thereof, and a storage medium storing a program.

Cross reference of related application

All disclosures of Japanese Patent Applications No. 2012-192575 and No. 2012-192577, filed on August 31, 2012, including specifications, claims, drawings and summary, are incorporated herein by reference.

In a DLP (Digital Light Processing (TM)) projector device using a semiconductor light emitting element such as an LED (Light Emitting Diode) or an LD (Semiconductor Laser) as a light source, The efficiency fluctuates greatly.

Therefore, it is important to consider the fluctuation of the luminous efficiency to enhance the quality of the projected image.

In this regard, for example, in Japanese Patent Application Laid-Open No. 2007-094108, there is disclosed a light emitting device of each color of an LED array, based on supply power waveform information that cancels the luminance variation of the LED array in each field period for each color component Thereby suppressing the influence of the heat fluctuation of the light source and maintaining the quality of the projected image at a high level.

In a projector apparatus, it is generally difficult to instantaneously perform switching of each color at a specific timing, and it is a general practice to set a period in which a plurality of light emission colors are mixed together temporarily. The switching period in which the plurality of colors are mixed is a "spoke period" due to a single-plate-type DLP system developed on the premise of using a color wheel. &Quot;. In the DLP method, the mixed light generated in the spoke period is measured and used effectively.

The semiconductor light emitting element realizes a current value which becomes a target value by using, for example, a current control technique such as PID control. However, the characteristics of the semiconductor light emitting device vary depending on the voltage or temperature to be applied, individual specificity of the device, and the like. Also, depending on the capacitor capacity in the circuit including the semiconductor light emitting element and the individual difference or driving state of the element such as the low-pass filter, the rising and falling characteristics of the light emission drive change.

When the characteristics of the semiconductor light emitting element change from rising to falling, the color as the mixed color light also changes. With respect to such changes in the characteristics of rising and falling of the semiconductor light emitting device, the techniques described in the above patent documents can not cope with it properly. If the actual light emission amount in the spoke period differs from the light emission amount measured in advance, the continuity of the gradation of the projected color is broken and the image quality is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a semiconductor light emitting device capable of maintaining continuity of color gradation in consideration of a change in light emitting state of a semiconductor light emitting element used in a light source, A projection method, and a storage medium in which a program is stored.

One of the preferred embodiments of the present invention is that,

A light source unit which circularly emits light of a plurality of colors by time division by light emission of a plurality of light emitting elements;

A display element which uses light from the light source, displays an image corresponding to the color component of the light, and forms an optical image by the reflected or transmitted light;

A projection unit for projecting the optical image formed by the display element toward a projection target;

A spoke setting means for setting a switching timing of the light of the plurality of colors and a spoke period around the switching timing;

Light source driving means for driving the light source section based on the switching timing and the spoke period set by the spoke setting means;

Detection means for detecting information indicating the amount of light for each color light emitted from the projection unit during the spoke period; And

And light source control means for controlling the light source to maintain the color balance of the color mixture in the spoke period at a desired balance based on the information indicating the light amount for each of the color lights obtained by the detection means

.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description together with the accompanying drawings. here,
1 is a block diagram showing a functional circuit configuration of a projector apparatus according to a first embodiment of the present invention.
2 is a block diagram illustrating an internal circuit configuration of the digital power supply of FIG. 1 according to the embodiment.
3 is a timing chart showing a segment switching pulse, a driving state of each light emitting element, and a display image according to the above embodiment.
4 is a timing chart of a current value measurement timing in a spoke period according to the embodiment.
FIG. 5 is a graph showing the rising characteristics of different spoke periods depending on the individual according to the embodiment.
FIG. 6 is a diagram illustrating an example of setting a delay time Tdl of a spoke period according to the embodiment.
FIG. 7 is a diagram showing switching states of various driving conditions in the spoke period according to the embodiment.
FIG. 8 is a view for explaining driving conditions and control contents of a digital power source for an LED emitting red (R) light according to the embodiment.
Fig. 9 is a flowchart showing processing contents relating to tone setting of a spoke period according to the third embodiment of the present invention.
10 is a view for explaining control contents for an LED emitting red (R) light according to the above embodiment.

Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. It should be noted, however, that the embodiments described below are subject to various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

(Embodiment 1)

Hereinafter, a first embodiment in which the present invention is applied to a DLP (registered trademark) type projector apparatus will be described with reference to the drawings.

1 is a diagram showing a schematic functional configuration of a projector apparatus 10 according to the present embodiment. 1, the input section 11 is constituted by, for example, a video input terminal of a pin jack (RCA) type, an RGB input terminal of a D-sub 15 type, an HDMI (High-Definition Multimedia Interface) . The analog or digital image signals of various standards input to the input unit 11 are digitized as required by the input unit 11 and then transmitted to the image conversion unit 12 through the system bus SB.

The image conversion unit 12 is also called a scaler or a formatter in general and transmits image data of an input digital value to image data of a predetermined format suitable for projection to the projection processing unit 13 .

At this time, data such as symbols representing various operating states for the OSD (On Screen Display) are superimposed on the image data by the image conversion section 12 as necessary, and the processed image data is transmitted to the projection processing section 13 do.

The projection processing unit 13 calculates a frame rate based on the image data which has been transmitted and which is obtained by multiplying the frame rate according to the predetermined format, for example, 120 [frames / second] And is driven to display a micromirror element 14 as a spatial light modulation element by time division driving.

The micromirror elements 14 are arranged so that the tilt angles of a plurality of micromirrors of, for example, WXGA (Wide eXtended Graphic Array) (1280 pixels × 800 pixels) / Off < / RTI > operation to display an image, thereby forming a light image by the reflected light.

On the other hand, the primary color lights of R, G and B are cyclically emitted from the light source unit 15 in a time division manner. The primary color light from the light source unit 15 is totally reflected by the mirror 16 and is irradiated to the micromirror element 14.

The optical image is formed by the reflected light from the micromirror element 14, and the formed optical image is projected and projected on a screen (not shown) to be projected through the projection lens unit 17. [

The light source unit 15 has an LED (light emitting diode) for emitting red light, an LD (semiconductor laser) for emitting blue laser light for irradiating the phosphor to emit green light, and an LED for emitting blue light.

The projection processing section 13 forms a light image by displaying an image on the micromirror element 14 and the light emission of each of the LED and LD as the light emitting element in the light source section 15 by a CPU 19 As shown in FIG. In addition, a segment switching timing pulse is sent to the digital power supply 18, and a command signal for power supply control is transmitted and received to the digital power supply 18. [

The digital power supply 18 generates and supplies a plurality of DC voltage values required for each circuit from an AC power supply applied for the projector apparatus 10. [ Further, the light source unit 15 is supplied with power necessary for driving the LED and the LD.

Fig. 2 shows a configuration of a portion for driving the light source unit 15 in the digital power supply 18. Fig. In other words, in the digital power supply 18, the voltage to be applied to the light source unit 15 is adjusted by the voltage adjustment unit 31. [ The current measuring unit 32 measures the current value (the light source current value) in a process in which the voltage-adjusted power is supplied to the load of the LED, LD, etc. in the light source unit 15. [ The result of the measurement in the current measuring section 32 is fed back to a DSP (Digital Signal Processor) 33. In response to the segment switching timing pulse and the power supply control command given from the projection processing section 13, the DSP 33 performs feedback control on the current value flowing to the light emitting element driven at that time point, 31).

The CPU 19 controls all the operations of the above circuits. The CPU 19 is directly connected to the main memory 20 and the program memory 21. The main memory 20 is constituted by, for example, an SRAM and functions as a work memory of the CPU 19. [ The program memory 21 is constituted by an electrically rewritable nonvolatile memory and stores an operation program executed by the CPU 19 and various types of fixed data. In other words, the CPU 19 executes the control operation in the projector apparatus 10 by using the main memory 20 and the program memory 21.

The CPU 19 executes various projection operations in accordance with a key operation signal from the operation unit 22. [

The operation section 22 includes a key operation section provided in the main body of the projector apparatus 10 and an infrared light receiving section for receiving infrared light from a remote controller (not shown) dedicated to the projector apparatus 10, And directly outputs the key operation signal based on the key operated by the remote controller or the remote controller to the CPU 19. [

The CPU 19 is also connected to the audio processing unit 23 via the system bus SB. The sound processing section 23 is provided with a sound source circuit such as a PCM sound source and converts the audio data given through the system bus SB during the projection operation into analog and drives the speaker section 24 to increase the volume, . Also, if necessary, a beep sound is generated.

Next, the operation of the above embodiment will be described.

The following operations all represent processing executed by the DSP 33 in the digital power supply 18 under the control of the CPU 19. [

3 shows the timing of the segment switching pulse input from the projection processing unit 13 to the digital power supply 18 and the timing of the image displayed by the light source unit 15 and the micromirror element 14 operating in synchronism therewith.

As shown in FIG. 3A, as the segment switching timing pulse is input from the projection processing section 13 to the digital power supply 18, the R, G, and B angles in synchronization with the rising timing tup of the pulse It is assumed that the segment is switched.

More specifically, a certain time Tsp is set as the spoke period from the rising timing (tup) of the segment switching timing pulse. The period from the end timing of the spoke period Tsp to the next rise timing tup is set as the period of each segment for projecting the primary colors R, G and B respectively.

Figs. 3 (B) to 3 (D) illustrate waveforms of driving currents of LEDs for red light, LDs emitting blue light for green excitation by the phosphors, and LEDs emitting blue light.

Here, the digital power supply 18 extinguishes the light emitting element driven in the previous segment in synchronization with the initial timing (tup) of the spoke period Tsp, and starts light emission of the light emitting element used in the next segment.

When the light emitting element is turned off, the drive current is suddenly lowered by stopping the driving after a minute waiting time.

On the other hand, at the start of light emission of the light emitting element, a time lag is generated for the rising period of the current from the above timing (tup), and a gentle slope current is lower than the slope when the current value is lowered.

Therefore, in the spoke period Tsp, light that gradually changes from the color of the immediately preceding segment to the color of the next segment is emitted from the light source unit 15. [

For example, in the spoke period Tsp between the R segment period Tr and the G segment period Tg, the light emitted from the light source unit 15 is gradually changed from red to green Change. In this spoke period Tsp, the projection processing section 13 causes the micromirror element 14 to display a deposit corresponding to yellow (Ye) which is a mixed color of red and green as shown in Fig. 3 (F) .

In the spoke period Tsp between the next G segment period Tg and the B segment period Tb, the light emitted from the light source section 15 gradually changes from green to blue. In the spoke period Tsp, the projection processing section 13 causes the micromirror element 14 to display the optical image corresponding to the cyan color Cy, which is a mixed color of green and blue.

Further, in the spoke period Tsp between the B segment period Tb and the R segment period Tr, the light emitted from the light source section 15 changes gradually from blue to red. In this spoke period Tsp, the projection processing unit 13 causes the micromirror element 14 to display a deposit corresponding to magenta (Mg) which is a mixture of blue and red.

On the other hand, in each of the segments of R, G, and B, the projection processing unit 13 causes the micro mirror device 14 to display the optical image corresponding to each color of the primary colors as described above.

4 is an example showing the control of the drive current of the semiconductor light emitting element in the light source section 15 by the digital power supply 18 during the spoke period Tsp. In this case, the semiconductor light emitting element of the light source 15 targets an LD that emits blue light to excite green (G) light by the phosphor. The black circles shown in Fig. 4 represent the sampling timing of the current value of the LD measured by the digital power source 18. Fig. As described above, the digital power supply 18 precisely measures the current value flowing through the light emitting element to be controlled and performs feedback control to the applied voltage value based on the measurement result, even in the spoke period, as in the segment period .

During the spoke period, the digital power supply 18 starts applying the voltage to the LD from the timing (tup) at the start, and measures the current value flowing therethrough. Specifically, the value of the current flowing in the LD gradually rises after the current rise time elapses from the timing tup due to the relationship of the forward falling voltage and the like. The digital power supply 18 shifts to the next segment period, here the G segment, while performing the feedback control so that the maximum value thereof maintains the target current iT in the figure.

The current rise time at which the current value does not rise from the above timing (tup) varies depending on the individual vehicle of the semiconductor light emitting device or factors of various driving conditions and can not be shortened.

Fig. 5 shows the difference in rise time due to these various factors by the individual characteristics of two LDs emitting blue light for exciting green (G) light by the phosphor.

In the current rise characteristic of the LD in the spoke period shown in Fig. 5A, the rise time? T1 is short, the slope of the rise after that is also sharp, and the time until the current value reaches the target current iT short. In comparison with this, in the current rise characteristic of the LD shown in Fig. 5B, the rise time? T2 is long and the slope of the rise is gentle until the current value reaches the target current iT Time is also getting longer.

Assuming that the area of the hatched portion shown in the figure is proportional to the amount of light emission, the individual LDs shown in FIG. 5A and the individual LDs shown in FIG. 5B are the LDs shown in FIG. The amount of light emission in the spoke period is obviously large. Therefore, with respect to an individual LD having better lift characteristics, by deliberately delaying the rise time, it is possible to adjust the amount of light emission equal to that of an individual LD whose rise characteristics are poor. As a result, it is possible to correct the display gradation of each color component in consideration of the falling characteristic and the rising characteristic, and project the image while maintaining the continuity of the gradation of each color component.

A measured value of the ratio of the area of the hatched portion to a rectangle formed by the spoke period Tsp and the target current iT is represented by alpha and a target value of the ratio of the area of the hatched portion is taken to be the delay time Tdl, of

Tdl = Tsp x (? -?) ... (One)

. The target value? Of the ratio of the area of the hatched portion is set by experiment so as to be the assumed minimum area so that "? -?" In the above formula (1) does not become a negative value.

The DSP 33 in the digital power supply 18 calculates the delay time Tdl so that the area of the hatched portion in the spoke period Tsp can be made constant. As a result, the quantity of emitted light can be kept constant in consideration of the individual difference of the semiconductor light emitting device.

Fig. 6 shows an example of setting the delay time Tdl. Here, the case where the delay time Tdl is set for the two LDs having the rising characteristics shown in Fig. 5 is shown.

That is, the delay time Tdl calculated in the equation (1) is set for the LD having higher response characteristics in the rising characteristic shown in FIG. 5 (A). Thus, as shown in Fig. 6A, the area of the hatched portion can be made equal to the area of the hatched portion of the ascending characteristic LD shown in Fig. 6B, and the amount of light emission in the spoke period Tsp Can be set evenly.

The target value beta and the time Tsp of the ratio in the above formula (1) are appropriately set from the maximum value and the minimum value of the assumed rise time.

This point is not limited to the rising characteristic for starting the light emission in the light emitting element in the spoke period, but may be a falling characteristic for stopping the light emission from the previous segment period in the spoke period, ), The same control can be executed.

Fig. 7 shows the switching states of various driving conditions in the spoke period. 7A illustrates the rising characteristic of the current value when the target current iT is maintained during the next segment period by starting the light emission in the spoke period as described in Figs. 4 to 6 . As described above, when the light emission is started in the unlit state and the current is increased, the degree of change varies from one light emitting element to another. This is because the width for raising the value of the current flowing in the load is the largest from the start to the target current value, and time is required. Since the change is large, the influence on the gradation expression is large.

FIG. 7B illustrates the falling characteristic of the current value when the light emission is stopped during the spoke period. When the light emission is stopped in this manner, the current value falls from the target current value to the unlit state in a very short time. Therefore, compared with the rise characteristics from the unlit state as shown in Figs. 4 to 6 and Fig. 7A, the influence is comparatively small. In this case, however, the gradation expression is affected by the individual difference of the light emitting element.

7C shows the relationship between the first target current iT1 and the second target current iT2 (iT1 < iT2) during the spoke period, for example, when the same light source is used continuously over a plurality of color segments. ) Of the current value is increased. In the case of increasing the current while maintaining the light emission as described above, the influence is comparatively small as compared with the rising characteristic from the unlit state as shown in Figs. 4 to 6 and Fig. 7 (A) And the like.

FIG. 7D illustrates the falling characteristic of the current value when the current value is decreased from the first target current iT1 to the second target current iT2 (iT1> iT2) during the spoke period. In the case of reducing the current while maintaining the light emission as described above, the falling characteristic to the unlit state as shown in FIG. 7B is more likely to be affected by the gradation expression by the individual difference of the light emitting element.

Considering the driving state during various spoke periods as described above, a case where the above formula (1) is further generalized will be considered.

The first current target value as the current target value before switching is A,

A second current target value which is a current target value after switching is B,

The average current measurement value of the spoke period is C,

The average current target value of the spoke period is D,

When the time of the spoke period is Tsp, the delay time Tdl is set to

Tdl = Tsp x (C-D) / (B-A) ... (2)

As shown in FIG.

The average current target value D and the time Tsp in the equation (2) are appropriately set in advance in accordance with the maximum value and the minimum value of the assumed average current measurement value C, respectively.

(1) and (2) due to a deviation from the continuity of the light emission amount and the current value, the light emission amount (illumination value) is estimated from an appropriate conversion formula from the current value, (1) or (2) may be used after adding a predetermined correction to the current value based on the amount of light emission.

Further, instead of estimating the light emission amount from the current value to the light emitting element as described above, for example, when the light emission amount (illumination value) of each light emitting element can be measured, The amount of light emission of each light emitting element may be measured directly instead of measuring the amount of light emitted.

In that case,

The amount of light emission before switching is A,

The amount of light emitted after conversion is B,

The measured value of the amount of emitted light in the spoke period is C,

The target value of the light emission amount in the spoke period is D

(2) can be used. With respect to the target value D of the light emission amount in the spoke period, it is determined by multiplying a certain coefficient by using an arithmetic expression prepared in advance for the light emission amount A before the switching and the light emission amount B after the switching. By doing so, it is possible to more precisely grasp the light emitting state of each light emitting element, and to realize precise gradation expression. Needless to say, the target value D of the light emission amount in the spoke period can be obtained by actually experimenting.

Next, timing for executing the above-described control will be described.

An example of driving conditions and control contents of the digital power supply 18 for the LED emitting red (R) light in the light source unit 15 will be described with reference to Fig.

The average current value is measured by the current measuring unit 32 when the DSP 33 drives the LED to emit light in the spoke period Tsp immediately before the R segment (step S101). Subsequently, the delay time Tdl is calculated using the above-described equation (1) or (2) (step S102).

The DSP 33 sets the calculated delay time Tdl (step S103). Then, the LED is driven to emit light with the delay time Tdl newly updated in the spoke period (Tsp) immediately before the R segment of the next image frame, and the average current value is measured again by the current measuring section 32 do. These series of processes are repeatedly executed.

By reflecting the measurement result in the spoke period in the same spoke period of the next image frame, it is possible to cope with the fluctuation of the driving state of the light emitting element immediately and to maintain the gradation representation of the projected image in a good state.

The above-described control is performed when, for example, the power is turned on, the predetermined continuous operation time (for example, 10 minutes, 30 minutes, 60 minutes, etc.) elapses, the projection mode (e.g., presentation mode, Or the like, is repeatedly performed a predetermined number of times, and then once stopped, and then waits until the timing of performing the above-described control. Further, for example, it may be performed continuously after the projection of the image is started until the projection of the image is finished.

In the above embodiment, for the sake of simplicity, for example, an LED emitting blue light and an LED emitting red (R) light have been described as an example to excite green (G) light with a phosphor. However, the DSP 33 in the digital power supply 18, which controls the driving state of the light source unit 15 with the actual projector apparatus 10, can emit light in all two colors that emit light in the spoke period, The driving state of each of the light emitting elements is measured, and the amount of light emission is adjusted for each color after considering the balance for each color. Thus, in each segment period of the primary colors of light (R, G, B), the gradation control is performed so that the color balance in the entire image frame is not disturbed in accordance with the degree of mixed color (complementary color) It is possible to realize accurate gradation expression taking advantage of the control of the period.

As described above, in the present embodiment, the delay time is set so that each color light emitted from the projection lens unit has a desired light emission amount, so that the continuity of the gradation of the color is obtained in consideration of the change of the light emission state of the light- It is possible to maintain the image projection.

As described in detail above, according to the present embodiment, it is possible to maintain the continuity of the gradation of the color while always taking the change of the light emitting state of the light emitting element used in the light source into consideration, and to always project with high image quality.

Further, in the above embodiment, the start timing of the light emitting element for emitting light in the spoke period is delayed by the control of the light source section 15 of the digital power supply 18. However, The continuity of the gradation of the color can be reliably maintained in consideration of the rising characteristic of the light-emitting element which is easy to receive.

Conversely, control may be performed so as to delay the end timing of the light emitting element of the color that starts light emission during the spoke period, so that continuity of the color gradation can be maintained without lowering the amount of light emission in the spoke period.

In the above embodiment, the light emitting element in the light source section 15 is made of a semiconductor light emitting element such as an LD or an LED. By using such a semiconductor light emitting element, high-speed responsiveness of the digital power supply 18 can be utilized, and precise control can be easily realized.

In the above embodiment, the digital power supply 18 samples the driving current of each light emitting element of the light source 15, calculates the delay time of the light emission timing during the spoke period from the driving current waveform of each sampled light emitting element, So that high-speed responsiveness as the digital power supply 18 can be utilized, and precise control can be easily realized.

(Second Embodiment)

Hereinafter, a second embodiment in which the present invention is applied to the same DLP projector apparatus as the above embodiment will be described with reference to the drawings.

The general functional configuration of the projector apparatus according to the present embodiment is basically the same as that shown in Fig. The configuration of the portion for driving the light source unit 15 in the digital power supply 18 is basically the same as that shown in Fig. Hereinafter, the same reference numerals are used for the same parts, and the illustration and description thereof are omitted.

Next, the operation of the above embodiment will be described.

The following operations all represent the processing executed by the DSP 33 in the digital power supply 18 under the control of the CPU 19. [

Under the condition that the voltage value to be adjusted by the voltage regulator 31 in the digital power supply 18 is constant, the target current value largely differs greatly in the gradation representation. In the case of using a semiconductor light emitting element such as an LD or an LED, the amount of control of the amount of emitted light is relatively large, and therefore, it is necessary to largely change the current value supplied to switch the brightness.

In the case where only the change of the color or the amount of light emission in the spoke period due to the change of the current value can be prevented, the control can be greatly simplified as compared with the method described in the first embodiment.

That is, an appropriate delay time is checked in correspondence with some drive current values assumed for each light emitting element, and stored in the DSP 33 as a lookup table or stored in an arithmetic expression.

The memory contents stored in the DSP 33 in this manner may be stored in the representative value by the magnitude of the individual difference of each light emitting element, or may be stored separately. An appropriate delay time Tdl is obtained and set from the stored result and the measurement result of the current value actually flowing through the light emitting element. Two concrete methods for estimating the delay time Tdl will be described below.

&Lt; First Estimation Method: Linear Interpolation >

In the first method, interpolation such as linear interpolation is performed from the measurement result of the current value and the current value by the current measuring unit 32 to set the delay time Tdl. In other words,

The appropriate delay time at current A is B,

The appropriate delay time at current C is D,

Let E be the current value of the light source to be set, and set the delay time Tdl to

Tdl = B + (D-B) (E-A) / (C-A) (3)

. Thus, by calculating the delay time Tdl by the calculation according to the equation (3), it is possible to maintain the color or amount of the spoke period Tsp constant and maintain the gradation representation accurately.

&Lt; Second Estimation Method: Step interpolation >

In the second method, a range of several current values and a stepwise delay time are stored in the DSP 33 in the form of a look-up table or an arithmetic expression, and stored in association with the range to which the actual current value belongs The delay time is acquired and set.

Setting the stepwise delay time in this manner is particularly effective, for example, in the case where the drive current value largely fluctuates due to switching of the operation mode involving an increase or a decrease in the amount of light emission in each light emitting element.

Even when both of the above two methods are employed, it is possible to maintain the continuity of the gradation of the color in consideration of the change of the light emitting state of the light emitting element used in the light source, and to always project with an accurate and high image quality. In addition, the configuration of the digital power supply 18 can be further simplified by largely reducing the control load applied to the DSP 33 in the digital power supply 18, compared with the first embodiment.

In the first and second embodiments, the light source unit 15 of the projector apparatus 10 emits the red (R) light and the blue (B) light directly by the LED, Green (G) light is obtained by exciting the light emitting element. However, the present invention does not limit the kind, number, and the like of the light emitting element which is a light source.

In addition to the above embodiment, for example, after measuring the amount of emitted light of each color of R, G, B in all the spoke periods of one frame of a color image, a constant ( constant) may be calculated by calculation, and the delay time of the emission timing in each spoke period may be collectively set based on this constant. This setting is such that the sum of light emission amounts during a plurality of spoke periods in one frame of a color image is a desired light emission amount.

In this manner, the display gradation of the color component in consideration of the falling characteristic and the rising characteristic in each spoke period is corrected, and the control is performed so that the overall color balance in the three spoke periods Tsp becomes appropriate through one frame of the color image Is executed. Further, since the delay setting of the light emission timing is performed for each frame of the color image, the load on the CPU 19 can be reduced as compared with the above embodiment.

In the above embodiment, the delay time of the emission timing in the spoke period is calculated from the driving current waveform of each sampled light-emitting element. However, the present invention is not limited to this, and the driving power waveform or the driving voltage waveform of each light- The delay time of the emission timing may be calculated.

(Third Embodiment)

Hereinafter, a third embodiment in which the present invention is applied to a DLP projector apparatus will be described with reference to the drawings.

The general functional configuration of the projector apparatus 10 'according to the present embodiment is basically the same as that shown in Fig. The configuration of the portion for driving the light source unit 15 in the digital power source 18 is basically the same as that shown in Fig. Hereinafter, the same reference numerals are used for the same parts, and the illustration and description thereof are omitted.

The projection processing section 13 of the projector apparatus 10 'according to the above-described embodiment has spoke calibration in which the display gradation corresponding to each light emitting element in a spoke period to be described later is set, And the display gradation of the micromirror element 14 is controlled in synchronization with the emission timing of each light emitting element during each spoke period based on the selected set.

Next, the operation of the above embodiment will be described.

Fig. 9 is a flowchart showing processing contents relating to color balance setting of a projected image executed by the CPU 19 as a main routine.

At first, the CPU 19 waits for the predetermined color balance setting timing (step S201).

As the predetermined timing for setting the color balance, for example, when a predetermined continuous operation time (for example, 10 minutes, 30 minutes, 60 minutes, etc.) A movie mode, a movie mode, a movie mode, a movie mode, a movie mode, a movie mode, a movie theater mode, etc.).

If the CPU 19 determines that the color balance setting is to be performed in step S201, it is determined that the first spoke period Tsp (the spoke period between the R segment period Tr and the G segment period Tg) The drive current values of the LEDs emitting red light and the LDs emitting blue light for green light emission are measured (step S202).

After performing the measurement in the first spoke period Tsp in step S202, the CPU 19 calculates the second spoke period Tsp (the interval between the G segment period Tg and the B segment period Tb) The driving current value of each of the LD emitting blue light for green light excitation and the LED emitting blue light is measured (step S203).

The CPU 19 also controls the LEDs emitting blue light and the LEDs emitting red light in the succeeding third spoke period Tsp (the spoke period between the B segment period Tb and the R segment period Tr) The drive current value is measured (step S204).

Thus, at the time when measurement of the drive current value of the light emitting element in each of the three spoke periods Tsp existing in one frame of the color image is completed, the CPU 19 determines, from the measurement results in each spoke period Tsp, The light emission amount of the R, G, B light is calculated and a constant indicating the total light emission amount in the first to third spoke periods Tsp is calculated by calculation (step S205).

Based on the calculation results, the CPU 19 causes the projection processing unit 13 to select one of the spoke calibration sets stored in advance in the plurality of sets, the one having the closest numerical value (step S206) (Step S207). That is, as shown in Fig. 6, the actual light emission amount in the spoke period differs from the light emission amount that has been measured in advance, in accordance with the change of the characteristics of the rise and fall of the semiconductor light emitting element. However, in the present embodiment, by resetting the spoke calibration set corresponding to the light emission amount of the spoke period at the present time, it is possible to project the image while maintaining the continuity of the gradation of each color component in consideration of the rising characteristic and the falling characteristic .

This setting is such that the sum of the amount of emitted light of color light projected during a plurality of spoke periods in one frame of the color image is a desired amount of emitted light. Thereby, the display gradation of the color component in consideration of the rising characteristic and the falling characteristic in each spoke period is corrected. As a result, control is performed so that the overall color balance in the three spoke periods Tsp becomes appropriate through one frame of the color image. Then, the CPU 19 returns to the processing from step S201 in preparation for performing the same control again.

Next, with reference to Fig. 10, the case of performing the above-described control continuously will be described by taking as an example the control contents executed by LEDs emitting red (R) light in the light source unit 15 as an example.

10, in the spoke period Tsp just before the R segment period Tr, the drive current value is measured by the current measurement unit 32 when the DSP 33 drives the LED to emit light (step &lt; RTI ID = 0.0 & S202). Subsequently, the same measurement is performed in the other two segment periods (step S205). The CPU 19 selects one of the plurality of calibration sets prepared in advance by the projection processing section 13 based on the calculated balance value and sets the selected set again in the projection processing section 13 (step S206 , S207). The display gradation in the micromirror element 14 when the LED emitting red light emits is controlled in the spoke period Tsp immediately before the R segment period Tr in the next image frame , The color balance of the complementary color image in the spoke period projected from the projection lens unit 17 is appropriately maintained by the tone correction of the R component.

In this spoke period Tsp, similarly to the above, the drive current value of the LED emitting red (R) light is measured by the current measurement section 32, and the same processing is repeatedly executed. The color balance setting may be performed consecutively for a predetermined number of times, for example. Further, it may be performed continuously after the projection of the image is started until the projection of the image is finished.

10 is a drawing showing control contents to be executed on LEDs emitting red (R) light in the light source unit 15. The light emitting elements other than the LDs emit blue light for exciting green (G) light, It goes without saying that the same processing is executed in parallel with the LEDs emitting blue (B) light.

By reflecting the measurement result in the spoke period in the spoke period of the next image frame as described above, the fluctuation of the driving state of the light emitting element can be immediately coped with. As a result, the gradation representation of the projected image can be maintained in a good state.

As described above, in the present embodiment, the R, G, and B lights emitted from the projection lens are always modulated to a predetermined desired light emission amount and then projected. Therefore, in consideration of a change in the light emitting state of the light emitting element used for the light source, It is possible to project an image with continuity of gradation.

As described in detail above, according to this embodiment, it is possible to maintain the continuity of the gradation of the color in consideration of the change in the light emitting state of the light emitting element used in the light source, so that the image can always be projected with high accuracy.

In the above embodiment, the calibration set for correcting the tone of the spoke period is stored in advance in the projection processing unit 13 for a plurality of sets, and the closest approximation to the color balance at a certain point of time is selected and set. As a result, the control contents in the CPU 19 and the projection processing section 13 can be simplified and the burden on each can be reduced.

Further, in the above embodiment, by controlling the display gradation of the micromirror element 14 in accordance with the start of light emission of the color light emitting element which starts emitting light during the spoke period, And the control is performed in accordance with the rising characteristic of the hour. This makes it possible to reliably maintain the continuity of the gradation of the color in consideration of the rising characteristic of the light emitting element which is easily influenced by the gradation expression.

In this embodiment, the display gradation of the micromirror element 14 is controlled in accordance with the characteristics of the light emitting element of the color stopping the light emission during the spoke period. This makes it possible to suppress color blurring caused by individual differences of the light emitting element, maintain the continuity of the gradation of the color, and always project with high image quality.

In the above embodiment, the light emitting element in the light source section 15 is made of a semiconductor light emitting element such as an LD or an LED. By using such a semiconductor light emitting element, high-speed responsiveness of the digital power supply 18 can be utilized, and precise control can be easily realized.

In the above embodiment, the digital power supply 18 measures the driving current value for the light emitting element, which corresponds to the light quantity of each light emitting element in the light source section 15. However, The configuration can be omitted and the configuration of the apparatus can be further simplified.

In the above embodiment, the case of controlling the gradation display by the micromirror element 14 in the spoke period is controlled so that the color balance can be obtained based on the driving current value of the light emitting element in the spoke period. However, as a result of setting the spoke calibration set back to the projection processing unit 13, the gradation of the complementary light in the spoke period, the primary color light in the R, G, and B segment periods, There is a possibility that it is shifted. In such a state, the ratio of the lengths of the R, G, and B segment periods in the purple color period is varied to adjust the color balance such that the color taste and gradation of white light match the initial setting You can.

By varying the ratio of the lengths of the purple color periods together, it is possible to widen the range of adjustment of the color balance and further increase the precision, thereby realizing the image projection in appropriate color balance at all times.

Further, not only the display gradation of the micromirror element 14 in the spoke period as described in the above embodiment can be controlled, but also the driving power of each light emitting element in the spoke period, for example, do.

By varying the driving power in the spoke period as described above, it is possible to absorb the difference between the rising characteristic and the falling characteristic caused by the individual difference of the light emitting element, thereby realizing image projection in proper color balance.

The present invention is not limited to the above-described embodiment, but may be applied to a case where a spoke corresponding to each light emitting element in each spoke period (Tsp) at each timing of the first to third spoke periods, Calibration may be set.

That is, the CPU 19 sets the driving current values of the LEDs emitting red light in the spoke period Tsp between the R segment period Tr and the G segment period Tg and the LDs emitting blue light for green light excitation And the light emission amount is calculated. Based on the calculation result, one of the spoke calibrations for Tr-Tg stored in the projection processing unit 13 in plural sets in advance is selected and set with the closest numerical value.

Subsequently, the CPU 19 identifies the LD for emitting blue light for green light excitation and the LED for emitting green light in the spoke period Tsp between the subsequent G segment period Tg and the B segment period Tb After calculating the amount of light emission by calculating the driving current value, one of the plurality of Tg-Tb spoke calibrations stored in advance in the projection processing unit 13 and having the closest numerical value is selected and set based on the calculation result.

The CPU 19 also measures the drive current values of the LEDs emitting blue light and the LEDs emitting red light in the spoke period Tsp between the subsequent B segment period Tb and the R segment period Tr And calculates the amount of light emission and selects one of the spoke calibrations for the Tb-Tr which is stored in the projection processing unit 13 in advance in the projection processing unit 13 and has the closest numerical value, based on the calculation result.

In this way, in the projection processing unit 13, the spoke calibration is stored for each of the three spoke periods existing in one frame of the color image in advance, and at the timing of each of the three spoke periods (Tsp) The calibration may be reset.

Even in this case, continuity of the gradation of the color can be maintained in consideration of the change in the light emitting state of the light emitting element used in the light source, and it is possible to always project with accurate and high image quality.

In the above embodiment, the spoke calibration during the spoke period is determined from the driving current waveforms of the sampled light-emitting elements. However, the present invention is not limited to this, and spoke calibration during the spoke period can be performed from the driving power waveform or the driving voltage waveform of the light- .

In the above embodiment, the light source unit 15 of the projector apparatus 10 'emits the red (R) light and the blue (B) light directly by the LED and simultaneously transmits the green The present invention is not limited to the type and the number of the light emitting devices which are the light sources.

In addition, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the gist of the present invention. The functions performed in the above-described embodiments may be combined as appropriate as possible. The above-described embodiment includes various steps, and various inventions can be extracted by appropriate combination according to a plurality of constituent requirements to be disclosed. For example, even if some constituent elements are deleted from the overall constituent requirements shown in the embodiment, the constitution from which the constituent elements are deleted can be extracted as an invention if the effect can be obtained.

Claims (14)

A light source unit which circularly emits light of a plurality of colors by time division by light emission of a plurality of light emitting elements;
A display element which uses light from the light source portion, displays an image corresponding to the color component of the light and forms an optical image by the reflected or transmitted light;
A projection unit for projecting the optical image formed by the display element toward a projection target;
A spoke setting means for setting a switching timing of the light of the plurality of colors and a spoke period around the switching timing;
A light source driving means for driving the light source section based on the switching timing and the spoke period set by the spoke setting means;
Detection means for detecting information indicating the amount of light for each color light emitted from the projection unit during the spoke period; And
A light source control means for controlling the light source so as to maintain the color balance of the mixed color in the spoke period on a desired balance based on the information indicating the amount of light for each color light obtained by the detection means;
/ RTI &gt;
The spoke setting means sets a plurality of spoke periods in one frame of the color image,
Wherein the light source control means sets the delay time of the light emission timing in the light source unit such that the sum of light emission amounts of the respective color lights projected from the projection unit during a plurality of spoke periods of one frame of the color image is set to a desired light emission amount, Device. The method according to claim 1,
Wherein the light source control means delays the light emission timing in the light source portion during the spoke period by the light source driving means based on information indicating the light amount for each color light obtained by the detection means. The method according to claim 1,
Wherein the light source control means controls the display gradation of the optical image formed by the display element during the spoke period based on information indicating the amount of light for each color light obtained by the detection means. The method according to claim 1,
Wherein the light source control means sets the delay time of the light emission timing in the light source unit so that each color light emitted from the projection unit in the one spoke period becomes a desired light emission amount. delete The method according to claim 1,
Wherein the detecting means samples at least one of a driving current waveform, a driving voltage waveform, and a driving power waveform of each light emitting element by the light source driving means,
Wherein said light source control means calculates and sets a delay time of a light emission timing in said light source portion during said spoke period from a result of sampling by said detection means. The method according to claim 1,
Further comprising storage means for previously storing the drive power of each light emitting element and the delay time of the emission timing during the spoke period in association with each other,
Wherein the light source control means reads and sets the delay time of the light emission timing from the storage means based on the detection result of the detection means. The method according to claim 1,
Wherein the detecting means measures an illuminance value for each color light emitted from the light source portion,
Wherein said light source control means calculates and sets a delay time of light emission timing in said light source section during said spoke period from said illumination value obtained by said detection means. The method according to claim 1,
Wherein said light source control means sets a delay time at the start of light emission in said light source section during a spoke period by said light source drive means. The method according to claim 1,
Wherein said light source control means sets a delay time at the end of light emission in said light source section during a spoke period by said light source drive means. The method according to claim 1,
Wherein the light emitting element of the light source unit uses at least one of a semiconductor laser and a light emitting diode. The method according to claim 1,
Wherein the light source control means sets the delay time of the light emission timing in the light source section in the same spoke period after one frame of the color image based on the detection result of the light amount in the spoke period obtained by the detection means. A light source unit which circularly emits light of a plurality of colors by time division by light emission of a plurality of light emitting elements; A display element that uses light from the light source portion, displays an image corresponding to the color component of the light, and forms an optical image by the reflected or transmitted light; And a projection unit for projecting the optical image formed by the display element toward a projection target,
A spoke setting step of setting a switching timing of the light of the plurality of colors and a spoke period around the switching timing;
A light source driving step of driving the light source section based on the switching timing and the spoke period set in the spoke setting step;
A detecting step of detecting information indicating the amount of light for each color light emitted from the projection unit during the spoke period; And
A light source control step of controlling the light source to maintain a color balance of the color mixture in the spoke period at a desired balance based on information indicating the light amount for each of the color lights obtained in the detection step
/ RTI &gt;
In the spoke setting step, a plurality of spoke periods are set in one frame of the color image,
The light source control step sets the delay time of the light emission timing in the light source unit so that the sum of light emission amounts of the respective color lights projected from the projection unit during a plurality of spoke periods of one frame of the color image is set to a desired light emission amount, Way. A light source unit which circularly emits light of a plurality of colors by time division by light emission of a plurality of light emitting elements; A display element that uses light from the light source portion, displays an image corresponding to the color component of the light, and forms an optical image by the reflected or transmitted light; And a projection unit for projecting the optical image formed by the display element toward the object to be projected, wherein the program is executed by a computer having a built-in device, the non-transitory computer-
The program causes the computer to function as:
A spoke setting means for setting a switching timing of the light of the plurality of colors and a spoke period around the switching timing;
Light source driving means for driving the light source section based on the switching timing and the spoke period set by the spoke setting means;
Detection means for detecting information indicating the amount of light for each color light emitted from the projection unit during the spoke period; And
A light source control means for controlling the light source so as to maintain the color balance of the mixed color in the spoke period at a desired balance based on the information indicating the light amount for each of the respective color lights obtained by the detection means
Lt; / RTI &gt;
The spoke setting means sets a plurality of spoke periods in one frame of the color image,
Wherein the light source control means sets the delay time of the light emission timing in the light source unit so that the sum of light emission amounts of the respective color lights projected from the projection unit during a plurality of spoke periods of one frame of the color image is set to a desired light emission amount, A temporary computer readable storage medium.

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