JP2013073068A - Light source device, projection device and light source control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device which achieves accurate gradation expression without luminance unevenness using a semiconductor light emitting device array.SOLUTION: A light source device includes: plural rows of G-LD array sections 18 where plural G-LDs are connected in series in each row as a unit; temperature sensors 31, 31 for detecting temperature at plural row positions in different heat environments with respect to the G-LD array sections 18; and a light source drive section 32 and a CPU 38 for dividing plural rows of LDs to control their drive states, respectively, on the basis of the detection result.

Description

  The present invention relates to a light source device, a projection device, and a light source control method suitable for a data projector using a plurality of semiconductor light emitting elements of the same color as light sources.

  As a light source for a projector, a light emitting diode (hereinafter referred to as “LED”) or a laser diode (hereinafter referred to as “LED”) that can perform color display with high brightness while consuming less power, instead of a conventional discharge tube such as a high-pressure mercury lamp. Many devices using a semiconductor light emitting element such as “LD”) are considered. (For example, Patent Document 1)

JP 2008-185924 A

  Consider the case where semiconductor light emitting elements are arranged in an array and used as a light source, including the techniques described in the above-mentioned patent documents. Semiconductor light emitting devices have large individual differences in forward drop voltage, and when connected in parallel, the voltage of all individuals is equalized. Therefore, current is concentrated sequentially from the individual with the lowest forward drop voltage. May progress.

  Therefore, when driving a plurality of semiconductor light emitting devices at the same time, it is necessary to connect the unit circuits in parallel to the power supply in a unit that is connected in series as much as possible and made constant current with resistors and active devices as a unit. There is.

  FIG. 10 shows an example of a light source array 1 in which semiconductor light emitting elements, for example, LEDs are arranged in 3 × 6. In the figure, the LEDs 1a, 1a,... Constituting the light source array 1 are driven with six rows connected in series and three rows connected in parallel.

  R1 to R3 indicated by broken lines in the figure indicate combinations of LEDs 1a, 1a,... That are connected in series. As can be understood from the figure, on the array arrangement, the LEDs 1a, 1a,... Belonging to R2 are arranged between the LEDs 1a, 1a,. Therefore, the LEDs 1a and 1a belonging to the row R2 are affected by the heat generated by the LEDs 1a and 1a belonging to the rows R1 and R3, and the temperature is likely to rise due to light emission driving as compared with the rows R1 and R3.

  FIG. 11 is a diagram showing the relationship between the drive current, temperature, and light output for the light source array 1. FIGS. 11A-1 to 11A-3 illustrate waveforms of currents that flow through the columns R1 to R3. As shown in these figures, when the LEDs 1a, 1a,... Of each column are driven with a current having a similar waveform during one cycle of light emission driving, the temperature for each column is as shown in FIGS. ) As shown.

  As described above, the LED 1a, 1a,... In the row R2 sandwiched between the rows R1, R3 has a larger temperature increase gradient due to light emission driving than the LEDs 1a, 1a,.

  An LED that is a semiconductor light emitting element has a light emitting efficiency that decreases as the temperature rises, and the light output decreases even with the same driving current. Therefore, the characteristics of the light output in each column are shown in FIG. To (C-3).

  That is, as shown in FIGS. 11 (C-1) to (C-3), the light output of each of the columns R1 to R3 is equal at the start of light emission at the beginning of the cycle, but the temperature rising gradient is the columns R1 and R3. Row R2 is higher than Therefore, the light output of each of the columns R1 to R3 at the end of the continuous light emission period has a clearly lower peak value L2 of the column R2 than the peak values L1 (= L3) of the columns R1 and R3.

  Thus, depending on the column position in the light source array 1, the light output distribution differs between the beginning and the end of the continuous light emission period. When a dark portion occurs in the light beam output from the light source array 1, luminance unevenness occurs in the light beam emitted from the light source, and it is difficult to accurately represent the projected image.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light source device, a projection device, and a light source capable of accurate gradation expression without luminance unevenness even when a semiconductor light emitting element array is used. It is to provide a control method.

  One aspect of the present invention is a plurality of columns of semiconductor light emitting devices connected in series in units of columns, and detection means for detecting temperatures at a plurality of column positions having different thermal environments with respect to the plurality of columns of semiconductor light emitting devices. And a drive control means for dividing the plurality of rows of semiconductor light emitting elements and controlling the driving states of the plurality of rows of semiconductor light emitting elements based on the detection results of the detection means.

  According to the present invention, even when a semiconductor light-emitting element array is used, there is no luminance unevenness and accurate gradation expression is possible.

The figure which shows the structure of the data projector apparatus which concerns on one Embodiment of this invention. The figure which shows the structure of the B-LD array part which concerns on the embodiment, and a temperature sensor, and its cooling direction. The figure which shows the difference of the column position and temperature environment which concern on the 1st operation example of the embodiment. 6 is a timing chart showing drive waveforms of the B-LD array unit according to the first operation example of the embodiment. 7 is a flowchart showing the content of a drive current correction process of the B-LD array unit according to the first operation example of the embodiment. 6 is a timing chart showing drive waveforms of the B-LD array section according to a second operation example of the embodiment. 7 is a flowchart showing the content of a drive current correction process of the B-LD array section according to a second operation example of the embodiment. 9 is a flowchart showing the content of a drive current correction process of the B-LD array section according to a third operation example of the embodiment. The figure which shows the other structure of the B-LD array part which concerns on the embodiment, and a temperature sensor, and its cooling direction. The figure which shows a general LED array and its cooling direction. The figure which shows the relationship between the drive current in the LED array of FIG. 10, temperature, and light output.

  Hereinafter, an embodiment in which the present invention is applied to a data projector apparatus of DLP (Digital Light Processing) (registered trademark) system will be described with reference to the drawings.

[Constitution]
FIG. 1 is a diagram showing a schematic functional configuration of a data projector apparatus 10 according to the present embodiment.
The input unit 11 includes, for example, a pin jack (RCA) type video input terminal, a D-sub 15 type RGB input terminal, and the like. Analog image signals of various standards input to the input unit 11 are digitized by the input unit 11 and then sent to the image conversion unit 12 via the system bus SB.

  The image conversion unit 12 is also referred to as a scaler and unifies input image data into image data of a predetermined format suitable for projection and sends the image data to the projection image driving unit 13.

  At this time, data such as symbols indicating various operation states for OSD (On Screen Display) is also superimposed on the image data by the image conversion unit 12 as necessary, and the processed image data is sent to the projection image driving unit 13. It is done.

  The projection image drive unit 13 multiplies a frame rate according to a predetermined format, for example, 60 [frames / second], the number of color component divisions, and the number of display gradations, in accordance with the transmitted image signal. The micromirror element 14 that is a spatial light modulation element is driven to display by high-speed time-division driving.

  This micromirror element 14 is turned on / off individually at a high speed for each inclination angle of a plurality of micromirrors arranged in an array, for example, WXGA (Wide eXtended Graphics Array) (horizontal 1280 pixels × vertical 800 pixels). By displaying the image, an optical image is formed by the reflected light.

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

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

  The light source unit 15 includes a B-LD array unit 18 in which a plurality of LDs emitting blue laser light, for example, a total of 18 rows of 3 rows × 6 columns, for example, are arrayed. In FIG. 1, only six pieces are extracted and shown with the plane of the paper as the column direction.

  The blue laser light emitted from the B-LD array unit 18 is totally reflected by the mirror array unit 19 at an angle of 90 °, and is converted into substantially parallel light beams by the condenser lens unit 20, and then transmitted through the dichroic mirror 21. Then, the integrator 22 converts the luminance distribution into a substantially uniform light beam, which is sent to the mirror 16.

  The light source unit 15 includes a G-LED 23 that emits green light. The green light emitted from the G-LED 23 is reflected by the dichroic mirror 24, further reflected by the dichroic mirror 21, and then converted into a luminous flux having a substantially uniform luminance distribution by the integrator 22 and sent to the mirror 16.

  Further, the light source unit 15 includes an R-LD array unit 25 in which a plurality of LDs emitting red laser light, for example, a total of 18 rows of 3 rows × 6 columns, for example, are arranged. In FIG. 1, only six pieces are extracted and shown with the plane of the paper as the column direction.

  The red laser light emitted from the R-LD array unit 25 is totally reflected at an angle of 90 ° by the mirror array unit 26, converted into substantially parallel light beams by the condenser lens unit 27, and then totally reflected by the mirror 28. The Further, the red laser light passes through the dichroic mirror 24 and is reflected by the dichroic mirror 21, and then is converted into a light beam having a substantially uniform luminance distribution by the integrator 22 and sent to the mirror 16.

As described above, the dichroic mirror 21 transmits blue light while reflecting green light and red light. The dichroic mirror 24 reflects green light while transmitting red light.
Within the B-LD array unit 18, for example, a plurality of, for example, two temperature sensors 31, 31 are provided at the center position. In FIG. 1, only one piece is extracted and shown with the paper surface as the row direction. The temperatures detected by these temperature sensors 31, 31 are sent to the light source driving unit 32.

  The light source driving unit 32 executes the light emission of the B-LD array unit 18.

  Within the R-LD array unit 25, for example, a plurality of, for example, two temperature sensors 35, 35 are provided at the center position. In FIG. 1, only one piece is extracted and shown with the paper surface as the row direction. The temperatures detected by these temperature sensors 35 and 35 are sent to the light source driving unit 36.

  The light source driving unit 36 performs light emission of the R-LD array unit 25.

  The G-LED 23 is driven by the light source driving unit 37 to emit green light.

  The CPU 38 controls all the operations of the above circuits. The CPU 38 is directly connected to the main memory 39 and the program memory 40. The main memory 39 is composed of, for example, an SRAM and functions as a work memory for the CPU 38. The program memory 40 is composed of an electrically rewritable nonvolatile memory, and stores an operation program executed by the CPU 38, various fixed data, and the like. The CPU 38 uses the main memory 39 and the program memory 40 to execute a control operation in the data projector device 10.

  The CPU 38 executes various projection operations according to key operation signals from the operation unit 41.

  The operation unit 41 includes a key operation unit provided in the main body of the data projector device 10 and a laser light receiving unit that receives infrared light from a remote controller (not shown) dedicated to the data projector device 10. A key operation signal based on the key operated by the key operation unit or the remote controller is directly output to the CPU 38.

  A specific configuration of the B-LD array unit 18 and the temperature sensors 31, 31 will be described with reference to FIG. The R-LD array unit 25 and the temperature sensors 35 and 35 are basically the same as the relationship between the B-LD array unit 18 and the temperature sensors 31 and 31, and only the reference numerals are shown in parentheses in the figure. The illustration is omitted as it is described.

  In the figure, the B-LD array section 18 is composed of 3 × 6 B-LDs 18a, 18a,... That emit blue laser light as described above. The 18 B-LDs 18a, 18a,... Are connected in series in 6 rows, and 3 rows are driven in parallel by the light source driving unit 32.

  In the figure, R11 to R13 (light source array group) indicated by broken lines respectively indicate combinations of B-LDs 18a, 18a,.

  Therefore, the temperature sensor 31 is arranged between the third and fourth B-LDs 18a and 18a located in the middle between the first row R11 and the second row R12, respectively. The temperature sensor 31 provided on the first row R11 side detects the representative values of the temperatures of the first row R11 and the third row R13 considered to be equivalent to the first row R11 with respect to the influence of heat. Shall.

  That is, when considered in units of columns, the first column R11 and the third column R13 are both adjacent to the second column R12 from one side, and the influence of heat applied from the B-LD 18a that is a heat source is It is considered equivalent.

  On the other hand, the temperature sensor 31 is similarly arranged between the third and fourth B-LDs 18a and 18a located in the center of the second row R12. The temperature sensor 31 provided on the second row R12 side detects a representative value of the temperature of the second row R12, which is considered to have a larger heat effect than both the first row R11 and the third row R13. It shall be.

  In other words, when considered in units of columns, the second column R12 is disposed between the first column R11 and the third column R13, and the influence of heat applied from the B-LD 18a that is a heat source. Is considered to be larger than the first column R11 and the third column R13, which are adjacent to the second column R12 only from one side.

[First operation example]
Next, a first operation example of the above embodiment will be described.
First, the basic concept of this embodiment will be described with reference to FIG. The figure shows changes in the temperature of the first column R11 (and the third column R13) and the temperature of the second column R12 during one light emission cycle of the B-LD array unit 18 (or R-LD array unit 25). Is shown.

  Here, the temperatures T1 and T2 of the LDs 18a and 18a in each column when a square wave pulse having a constant current value is applied until a timing tm in the middle of one cycle from the timing t0 to the timing t1 are shown.

  The temperature T1 in the first row R11 (and the third row R13) rises from the temperature value Ta at the timing t0 at the beginning of the cycle to the temperature value Tb at the timing tm by light emission driving, and then the light emission driving. Is repeated, and the pattern of sequentially decreasing and returning to the temperature value Ta again until the timing t1 (timing t0 of the next cycle) at which light emission is driven again in the next cycle is repeated.

  The temperature T2 in the second row R12 increases from the temperature value Tc at the timing t0 at the beginning of the cycle to the temperature value Td (Tb <Td) at the timing tm by the light emission driving, and then the light emission driving is performed. A pattern is repeated in which the temperature is lowered and then returned to the temperature value Tc again until the timing t1 (timing t0 of the next cycle) at which light emission is driven again in the next cycle.

The fluctuation range ΔT1 of the temperature T1 and the fluctuation range ΔT2 of the temperature T2 in one cycle
ΔT1 = Tb−Ta
ΔT2 = Td−Tc
In this case, the current value applied to the B-LDs 18a, 18a,... Belonging to the second row R12 is controlled, and the tm in the cycle is determined based on the ratio “ΔT2 / ΔT1” of the two fluctuation ranges ΔT1, ΔT2. If only the increase is made, it is possible to cancel the decrease in the light emission efficiency due to the thermal load in the second column R12, and to obtain an optical output equivalent to that of the first column R11 (and the third column R13).

  FIG. 4 shows a driving current for the B-LD array unit 18 (and the R-LD array unit 25) executed by the light source driving unit 32 (and the light source driving unit 36) under the control of the CPU 38 based on such a concept. It is a figure which shows the relationship between temperature and light output.

  4A-1 to 4A-3 illustrate waveforms of currents that flow through the columns R11 to R13. The B-LDs 18a, 18a,... In the first row R11 and the third row R13, which are considered to have a relatively low influence of heat, are driven as shown in FIGS. 4 (A-1) and (A-3). Driving is performed with a square-wave current value so that the current value inside is constant and does not change.

  On the other hand, for the B-LDs 18a, 18a,... In the second row R12, where the influence of heat is relatively high and the light emission efficiency is lower than that in the first row R11 and the third row R13, FIG. As shown in -2), driving is performed with a current value that rises in the latter half of the light emission period so as to cancel out the fluctuation range corresponding to the column position described above.

  As a result, the temperature for each column detected by the temperature sensors 31 and 31 is as shown in FIGS. 4B-1 to 4B-3, as compared with the first column R11 and the third column R13. The gradient of the temperature rise in the second row R12 becomes larger.

  However, although the light emission efficiency of the B-LDs 18a, 18a,... In the column is further lowered by intentionally inclining the drive current value of the second column R12, FIG. As shown in C-3), the light outputs L11 to L13 of each column at the end of the continuous light emission period can be made equal. As a result, the light outputs of each column R11 to R13 are continuously emitted from the start of light emission at the beginning of the cycle. It can be evenly aligned up to the end of.

  Note that, for example, a drive indicating how much the current value should be increased at the timing tm with respect to a state where the value of “ΔT2 / ΔT1” and the current value being driven in the second column R12 are constant. The relationship with the current correction amount may be experimentally stored in advance in the program memory 40, and the drive current correction value corresponding to the calculated “ΔT2 / ΔT1” may be referred to.

  Next, FIG. 5 illustrates how the first operation example of the above embodiment actually operates using a flowchart. The figure shows the projection operation of the above-described embodiment in the B-LD array unit 18 and is executed based on the control of the CPU 38 at the time of image projection. The CPU 38 reads out the operation program and data stored in the program memory 40, develops and stores them in the main memory 39, and executes the operation program.

  At the beginning of the processing, the CPU 38 waits until the measurement timing is reached by repeatedly determining whether or not the measurement timing has been set once, for example, once per minute (step S101).

  Then, when the measurement timing is reached, it is determined in the above step S101, and the first temperature sensor 31 provided in the first row R11 and the temperature sensor 31 provided in the second row R12 are used for the first time. The temperature value Ta of the first column R11 and the temperature value Tc of the second column R12 are measured at the light emission drive start timing t0 during one cycle period in the frame, and at the light emission drive stop timing tm, the first column R11 is measured. The temperature value Tb of R11 and the temperature value Td of the second row R12 are measured (step S102).

  Next, the CPU 38 calculates the temperature fluctuation range ΔT1 of the first column R11 and the temperature fluctuation range ΔT2 of the second column R12 within one cycle from the measured temperatures (step S103).

  The CPU 38 calculates the ratio “ΔT2 / ΔT1” between ΔT1 and ΔT2 from the calculated fluctuation width ΔT1 and fluctuation width ΔT2 within one cycle (step S104).

  Based on this calculation result, the CPU 38, for example, the relationship between the value of “ΔT2 / ΔT1” stored in advance in the program memory and the drive current correction amount for the B-LDs 18a, 18a,... Belonging to the second column R12. Are determined for the B-LDs 18a, 18a,... Belonging to the second column R12 (step S105).

  In the second frame, which is the next frame after the first frame, the CPU 38 performs the process for the B-LDs 18a, 18a,... In the second column R12 based on the correction amount of the drive current value determined in step S105. 4 (A-2), the drive is performed with the current value that increases in the latter half of the light emission period, and at the same time, the B-LDs 18a, 18a,. Then, as shown in FIGS. 4A-1 and 4A-3, driving is performed with a square-wave current value so that the current value during driving is constant and does not change (step S106).

  Assuming that the processing for one frame has been completed, the CPU 38 returns to the processing from step 101 and prepares for the next measurement timing.

  As described above in detail, according to the present operation example, the drive current value is varied taking into consideration that the influence of heat differs depending on the column position in the B-LD array unit 18 (and the R-LD array unit 25). By driving in this manner, unevenness in light output over the entire array surface can be eliminated, and unevenness in luminance in the light source light beam can be eliminated, so that the entire projected image can be represented with correct gradation.

  In particular, in the above operation example, the driving amount of the B-LDs 18a, 18a,. .. By intentionally increasing the drive amount of the B-LDs 18a, 18a,... To prevent the light output of the B-LDs 18a, 18a,. By canceling the light emission efficiency due to the influence of heat different for each column, it is possible to obtain an optical output equivalent to that for all the columns.

[Second operation example]
Next, a second operation example of the above embodiment will be described.
The basic concept of this embodiment is as described in FIG. 3 above, and a detailed description thereof is omitted.

  FIG. 6 shows the drive current and temperature for the B-LD array unit 18 (and the R-LD array unit 25) and the light output executed by the light source drive unit 32 (and the light source drive unit 36) under the control of the CPU 38. It is a figure which shows a relationship.

  FIGS. 6A-1 to 6A-3 illustrate waveforms of currents that flow through the columns R11 to R13.

  For the B-LDs 18a, 18a,... In the second row R12, which is relatively highly affected by heat and has a lower light emission efficiency than the first row R11 and the third row R13, FIG. As shown in FIG. 5, driving is performed with a square-wave current value so that the current value during driving is constant and does not change.

  On the other hand, as shown in FIGS. 6 (A-1) and (A-3), for the B-LDs 18a, 18a,... Driving is performed with a current value that decreases in the latter half of the light emission period so as to cancel out the fluctuation width corresponding to the column position.

  As a result, the temperature for each column detected by the temperature sensors 31 and 31 is as shown in FIGS. 6B-1 to 6B-3, and the first column R11 and the second column R12 are compared with the second column R12. The gradient of the temperature rise in the third row R13 becomes smaller.

  However, by intentionally providing a slope that sequentially decreases the drive current values of the first row R11 and the third row R13, the influence of heat as shown in FIGS. 6C-1 to 6C-3. Are intentionally lowered so that the optical outputs of the B-LDs 18a, 18a,... Of the first row R11 and the third row R13, which are relatively low, become equal to the optical outputs of the G-LDs 18a, 18a,. As a result, the optical outputs of the respective rows R11 to R13 can be made equal.

  For example, in the value of “ΔT2 / ΔT1” and in the first column R11 and the third column R13, how much the current value is decreased at the timing tm as compared to when the current value during driving is constant. The relationship with the drive current correction amount indicating whether or not it is good may be experimentally stored in advance in the program memory 40, and the drive current correction value corresponding to the calculated “ΔT2 / ΔT1” may be referred to. .

  Next, FIG. 7 illustrates how the second operation example of the above embodiment actually operates using a flowchart. The figure shows the projection operation of the above-described embodiment in the B-LD array unit 18 and is executed based on the control of the CPU 38 at the time of image projection. The CPU 38 reads out the operation program and data stored in the program memory 40, develops and stores them in the main memory 39, and executes the operation program.

  At the beginning of the process, the CPU 38 waits until the measurement timing is reached by repeatedly determining whether or not the measurement timing has been set once, for example, once per minute (step S201).

  Then, when the measurement timing is reached, it is determined in step S201, and the first frame is again formed by the temperature sensor 31 provided in the first row R11 and the temperature sensor 31 provided in the second row R12. The temperature value Ta of the first column R11 and the temperature value Tc of the second column R12 at the light emission drive start timing t0 during one cycle period are measured, and the first column R11 at the light emission drive stop timing tm is measured. And the temperature value Td of the second row R12 are measured (step S202).

  Next, the CPU 38 calculates the temperature fluctuation range ΔT1 of the first column R11 and the temperature fluctuation range ΔT2 of the second column R12 within one cycle from the measured temperatures (step S203).

  The CPU 38 calculates the fluctuation range ΔT1 and fluctuation range ΔT2 in the calculated one cycle, and calculates the ratio “ΔT2 / ΔT1” between the ΔT1 and ΔT2 (step S204).

  Based on this calculation result, the CPU 38 drives the values of “ΔT2 / ΔT1” stored in advance in the program memory 40 and the B-LDs 18a, 18a,... Belonging to the first column R11 and the third column R13, for example. Referring to the table showing the relationship with the current correction amount, the drive current value correction amount for the B-LDs 18a, 18a,... Belonging to the first column R11 and the third column R13 is determined (step S205).

  Next, in the second frame, which is the next frame after the first frame, the B-LDs 18a, 18a of the first column R11 and the third column R13 based on the correction amount of the drive current value determined in step S204. ,..., As shown in FIGS. 6A-1 and 6A-3, driving is performed with a current value that decreases in the latter half of the light emission period, and at the same time, B in the second column R12 As shown in FIG. 6A-2, the -LDs 18a, 18a,... Are driven with a square wave current value so that the current value during driving is constant and does not change (step S206).

  The CPU 38 has completed the process for one frame as described above, and returns to the process from step 201 to prepare for the next measurement timing.

  As described above in detail, also in this operation example, the drive current value is varied in consideration of the influence of heat depending on the column position in the B-LD array unit 18 (and the R-LD array unit 25). By driving, unevenness in light output over the entire surface of the array can be eliminated, and unevenness in luminance in the light beam of the light source light can be eliminated, so that the entire projected image can be expressed with correct gradation.

  In particular, in the above-described operation example, the influence of heat is much less without changing the drive amount of the B-LDs 18a, 18a,... The light output of the B-LDs 18a, 18a,... Of the rows not affected by heat is intentionally suppressed by reducing the driving amount of the B-LDs 18a, 18a,. An optical output equivalent to that of all the columns can be obtained without reducing the efficiency.

  In the first operation example, the drive amount of the B-LDs 18a, 18a,... In the row where the influence of heat is higher is set to be greater than the drive amount of the B-LDs 18a, 18a,. By intentionally increasing it, it is assumed that the light output of the B-LDs 18a, 18a,...

However, by performing such control, the B-LDs 18a, 18a,... In the row where the influence of heat becomes higher is further affected by heat, and at the same time, the light emission efficiency is further lowered.
In addition, it does not necessarily return to the initial temperature of the cycle by radiating heat within a period of no light emission within one cycle, and it falls into a vicious circle in which the effects of heat accumulate sequentially and further lower the light emission efficiency. The situation is also conceivable.

  On the other hand, in the second operation example, the drive amount of the B-LDs 18a, 18a,... In the row where the influence of heat is not so high is larger than the drive amount of the B-LDs 18a, 18a,. By intentionally reducing the light output of the B-LDs 18a, 18a,... In the row where the influence of heat is not so high, the light output of the B-LDs 18a, 18a,. It was supposed to be.

However, by performing such control, the B-LDs 18a, 18a,... In the row where the influence of heat is not so high may intentionally attenuate the light output within the cycle period even though there is still power. Driven.
Therefore, the control method described in the first operation example and the control method described in the second operation example may be combined.
For example, in the control method described in the first operation example, the drive amount of the B-LDs 18a, 18a,... In the row where the thermal load becomes higher, for example, light emission from a predetermined timing within one cycle, that is, light emission drive start timing t0. A threshold is set for a drive current value (determination drive current value I0) applied to the B-LDs 18a and 18a of the second column R12 at a predetermined timing before the drive stop timing tm, and the threshold is set. When the value is about to be exceeded, comprehensive control that switches to the control method described in the second operation example may be executed.

[Third operation example]
That is, assuming that the combined operation of the first and second operation examples of the above embodiment is the third operation example, in the control method described in the first operation example, the second column at a predetermined timing within one cycle. When the drive current value applied to the B-LDs 18a, 18a... Of R12 exceeds the threshold value Ith, the emergency correction amount calculated by subtracting a predetermined ratio from the drive current value equal to the threshold value Ith. The B-LDs 18a, 18a,... Of the second column R12 are driven with the drive current value based on the above.

  Then, the B-LDs 18a, 18a,... In the second column R12 are driven with the drive current value based on the urgent correction amount, and the first column as shown in the second operation example is left. The drive amount of the B-LDs 18a, 18a,... In the R11 and the third row R13 is intentionally reduced from the drive amount of the B-LDs 18a, 18a,.

  As a result, the temperature of the B-LDs 18a, 18a,... In the second row R12 gradually decreases, and the luminous efficiency of the B-LDs 18a, 18a,. Further, along with this, the decreasing range of the current values of the B-LDs 18a, 18a,... In the first column R11 and the third column R13 is reduced, and finally the first column R11 and the third column R11. The current values of the B-LDs 18a, 18a,... In the row R13 are square wave current values that are constant and do not change during driving.

  The drive current values of the B-LDs 18a, 18a,... In the first column R11 and the third column R13 become a square wave current value that is constant and does not change during driving, that is, the first column. The temperature of the B-LDs 18a, 18a,... In the second column R12 has sufficiently decreased at the timing when the correction amount of the drive current value for the B-LDs 18a, 18a,. Judgment is made and the control shown in the second operation example is released.

  The threshold value Ith can be determined based on the allowable current value of the light emitting element set in order to prevent the LD from destructive deterioration.

  In addition, the predetermined ratio used when calculating the emergency correction amount is bright for human eyes even when the correction amount is switched to the emergency correction amount during the control of the first operation example. Preferably, the ratio is such that it cannot be recognized that the change has occurred.

  Next, how the third operation example combining the first and second operation examples of the above-described embodiment actually operates will be described using a flowchart. FIG. 8 is a flowchart of this operation. The figure shows the projection operation of the above-described embodiment in the B-LD array unit 18 and is executed based on the control of the CPU 38 at the time of image projection. The CPU 38 reads out the operation program and data stored in the program memory 40, develops and stores them in the main memory 39, and executes the operation program.

  At the beginning of the process, the CPU 38 waits until the measurement timing is reached by repeatedly determining whether or not the measurement timing has been set once, for example, once per minute (step S301).

  Then, when the measurement timing is reached, it is determined in step S301, and the CPU 38 detects the determination drive current value I0 applied to R12 at a predetermined timing within one cycle, and this I0 is preliminarily stored in the program memory. The stored threshold value Ith is compared (step S302).

  When it is determined that the reference drive current value I0 is lower than the threshold value Ith, the first frame is newly formed by the temperature sensor 31 provided in the first column R11 and the temperature sensor 31 provided in the second column R12. The temperature value Ta of the first column R11 and the temperature value Tc of the second column R12 at the light emission drive start timing t0 during one cycle period are measured, and the first column R11 at the light emission drive stop timing tm is measured. And the temperature value Td of the second column R12 are measured (step S303).

  Next, the CPU 38 calculates the temperature fluctuation width ΔT1 of the first column R11 and the temperature fluctuation width ΔT2 of the second column R12 in one cycle from the measured temperatures (step S304), and further ΔT1, The ratio “ΔT2 / ΔT1” of ΔT2 is calculated (step S305).

  Then, the CPU 38, for example, stores a table showing the relationship between the value of “ΔT2 / ΔT1” stored in advance in the program memory 40 and the drive current correction amount for the B-LDs 18a and 18a belonging to the second column R12. Referring to FIG. 8, the correction amount of the drive current value for the B-LDs 18a, 18a,... Belonging to the second column R12 is determined (step S306).

  Next, the CPU 38 changes the B-LDs 18a, 18a,... In the second column R12 based on the correction amount of the drive current value determined in the step S305 in the second frame that is the next frame after the first frame. On the other hand, as shown in FIG. 4A-2, driving is performed with a current value that increases in the latter half of the light emission period, and at the same time, the B-LDs 18a and 18a in the first column R11 and the third column R13 are used. ,... Are driven with a square wave current value so that the current value during driving is constant and does not change as shown in FIGS. 4A-1 and 4A-3 (step S307). .

  The CPU 38 has completed the processing for one frame as described above, and returns to the processing from step 301 again to prepare for the next measurement timing.

  In step S302, when it is determined that the reference drive current value I0 of the second column R12 is higher than the set threshold value Ith, the temperature sensor 31 provided in the first column R11 again; By the temperature sensor 31 provided in the second column R12, the temperature value Ta of the first column R11 and the temperature value Tc of the second column R12 at the light emission drive start timing t0 during one cycle period in the first frame And the temperature value Tb of the first column R11 and the temperature value Td of the second column R12 at the light emission drive stop timing tm are measured (step S308).

  Next, the CPU 38 calculates the temperature fluctuation range ΔT1 of the first column R11 and the temperature variation ΔT2 of the second column R12 within one cycle from the measured temperatures (step S309), and further ΔT1. , ΔT2 ratio “ΔT2 / ΔT1” is calculated (step S310).

Next, the CPU 38 reads out the emergency correction amount stored in advance in the program memory 40. (Step S311)
Next, the CPU 38, for example, the relationship between the value of “ΔT2 / ΔT1” stored in advance in the program memory 40 and the drive current correction amount for the B-LDs 18a, 18a,... In the first column R11 and the third column R13. Are determined for the B-LDs 18a, 18a,... In the first column R11 and the third column R13 (step S312).

  Next, the CPU 38 is the second frame that is the next frame after the first frame, and the B-LDs 18a and 18a in the first column R11 and the third column R13 based on the correction amount of the drive current value determined in step 104 above. ,... Are driven by a current value that decreases with the latter half of the light emission period, as shown in FIGS. 6A-1 and 6A-3, and at the same time, the B-LD 18a in the second column R12. , 18a,... Are driven with a current value based on the emergency correction amount read in step S310. (Step S313).

  Next, the CPU 38 detects the correction amount of the drive current value applied to the B-LDs 18a and 18a of the first column R11 and the third column R13 in one cycle, and determines whether this correction amount is 0 or not ( Step 314).

  When determining that the detected correction amount is not 0, the CPU 38 returns to the process from step S308 and continues the process.

  If it is determined that the detected correction amount is 0, the CPU 38 has completed the processing for one frame, returns to the processing from step 301 again, and prepares for the next measurement timing.

  In this way, when it is determined that there has been a limit to the control method for changing the driving state of the elements in the other column with reference to the driving state of the elements in one column, this time, the control target column is inverted. By executing the control to change the drive state of the elements in one column on the basis of the drive state of the elements in the other column, avoiding a heavy burden on some elements It is possible to correctly express the gradation of the entire projected image in a stable state for a long time.

  In the above embodiment, the B-LD array unit 18 and the R-LD array unit 25 are composed of, for example, 3 × 6 total 18 LDs, one column is connected in series, and three columns are connected in parallel. It was supposed to be driven. In addition, the B-LD array unit 18 and the R-LD array unit 25 include temperature sensors 31 and 35 between the third and fourth LDs located in the center of the first column and the second column, respectively. Was supposed to be placed.

  As described above, the present embodiment detects the representative values of the temperatures of the rows with high and low thermal loads, predicts the temperature distribution on the entire array surface based on the detection results, and the B-LD array unit 18. Each column of the B-LDs 18a and 18a provided in the (and R-LD array unit 25) is controlled.

  For this reason, it is possible to correctly express the entire gradation of the projected image without installing temperature sensors 31 and 35 in each of the first column R11, the second column R12, and the third column R13. .

However, the present invention does not limit the configuration of the array arrangement of the semiconductor light emitting elements, the number and positions of the temperature sensors, and the like.
FIG. 9 shows another configuration example of the B-LD array unit 18 (and the RB-LD array unit 25). Here, it is assumed that the B-LD array unit 18 is composed of 5 × 6 total 30 LDs, 6 in a row are connected in series, and 5 rows are driven in parallel. In addition, the B-LD array unit 18 and the R-LD array unit 25 are positioned at the center of the first column and the third column, respectively, in order to measure the temperature of the high and low heat affected rows. Temperature sensors 31, 31 (35, 35) are arranged between the third and fourth LDs.

  A plurality of temperature sensors arranged in an array of semiconductor light emitting elements are also provided at positions where the average temperature in the columns connected in series can be detected, and at least two in the columns with high and low heat effects. As a result, the temperature distribution of the entire array surface can be predicted based on the temperature detection result, and the LDs provided in the B-LD array unit 18 and the R-LD array unit 25 can be controlled.

  Even if a forced cooling system such as a cooling fan is provided in the semiconductor light source element array, it is considered that the distribution regarding the influence of heat generated in the array on the detection result of the temperature sensor is uniquely determined. The drive current of the semiconductor light emitting elements in each column corresponding to the detection result is stored in advance in the program memory 40 as a look-up table, and the CPU 38 drives by referring to the look-up table according to the detection result of the temperature sensor. The amount may be determined.

  In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the functions executed in the above-described embodiments may be combined as appropriate as possible. The above-described embodiment includes various stages, and various inventions can be extracted by an appropriate combination of a plurality of disclosed constituent elements. For example, even if several constituent requirements are deleted from all the constituent requirements shown in the embodiment, if an effect is obtained, a configuration from which the constituent requirements are deleted can be extracted as an invention.

Hereinafter, the invention described in the scope of claims of the present application will be appended.
The invention according to claim 1 is composed of a plurality of semiconductor light emitting elements connected in series, and a plurality of light source column groups that can be driven and controlled in units of columns, and the temperature of different light source column groups among the plurality of light source column groups. It comprises detection means for detecting each of them, and drive control means for controlling the driving states of the semiconductor light emitting elements of the plurality of light source array groups based on the detection results of the detection means.

  According to a second aspect of the present invention, in the first aspect of the present invention, the drive control means is configured so that the drive light control means within a continuous light emission period of the semiconductor light emitting elements for each of the plurality of light source array groups, based on a detection result of the detection means. The driving states of the semiconductor light emitting elements of the plurality of light source array groups are respectively controlled in accordance with the ratio of the temperature rise degrees.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the detection means is a semiconductor of the first light source array group having a different thermal environment among the semiconductor light emitting elements of the plurality of light source array groups. The temperature of the light emitting element and the semiconductor light emitting element of the second light source array group are detected.

  The invention according to claim 4 is the invention according to claim 3, wherein the first row of semiconductor light emitting devices has a higher temperature rise than the second row of semiconductor light emitting devices, and the control means includes: The drive current applied to the semiconductor light emitting elements in the second column so that the drive current value when the drive is stopped is higher than the drive current value when the drive is started. The driving state of the first semiconductor light emitting element is controlled to be higher than the value.

  The invention according to claim 5 is the invention according to claim 3, wherein the semiconductor light emitting elements in the first column have a higher temperature rise than the semiconductor light emitting elements in the second column, and the control means includes: The driving current applied to the semiconductor light emitting elements in the first column so that the driving current value at the time of stopping driving is lower than the driving current value at the time of starting driving. The driving state of the second semiconductor light emitting element is controlled so as to be lower than the value.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to third aspects, the drive control means sets in advance a range for limiting a drive condition of the semiconductor light emitting element, and the drive condition reaches the range. The drive power increase / decrease relationship controlled up to that point and the light source array group to be controlled by the semiconductor light emitting element are inverted and set.

  The invention according to claim 7 further comprises cooling means for cooling the semiconductor light emitting elements of the plurality of light source array groups in the invention according to any one of claims 1 to 6, wherein the detecting means is the cooling means. It is characterized in that the temperatures of a plurality of light source array groups having different cooling effects are detected.

  The invention according to claim 8 is composed of a plurality of semiconductor light emitting elements connected in series, and the temperature of different light source column groups among the plurality of light source column groups that can be driven and controlled in units of columns and the plurality of light source column groups. A light source having a detection unit for detecting each of them, a drive control unit for controlling the driving states of the semiconductor light emitting elements of the plurality of light source array groups based on the detection results in the detection unit, and an input unit for inputting an image signal; A light image forming means for forming a light image using light from the light source based on an image signal input by the input means; and a projection for projecting the light image formed by the light image forming means toward a projection target. Means.

  The invention according to claim 9 is a light source control method in an apparatus comprising a plurality of light source column groups that are composed of a plurality of semiconductor light emitting elements connected in series and can be driven and controlled in units of columns. A detecting step for detecting temperatures of different light source row groups in the group, and a driving control step for controlling the driving states of the semiconductor light emitting elements of the plurality of light source row groups based on the detection results in the detecting step. It is characterized by that.

  DESCRIPTION OF SYMBOLS 1 ... Light source array, 1a ... LED, 10 ... Data projector apparatus, 11 ... Input part, 12 ... Image conversion part, 13 ... Projection image drive part, 14 ... Micromirror element, 15 ... Light source part, 16 ... Mirror, 17 ... Projection lens unit, 18 ... B-LD array part, 18a ... B-LD, 19 ... Mirror array part, 20 ... Condensing lens part, 21 ... Dichroic mirror, 22 ... Integrator, 23 ... G-LED, 24 ... Dichroic mirror 25 ... R-LD array part, 26 ... Mirror array part, 27 ... Condensing lens part, 28 ... Mirror, 31 ... Temperature sensor, 32 ... Light source drive part, 35 ... Temperature sensor, 36 ... Light source drive part, 37 ... Light source drive unit, 38 ... CPU, 39 ... main memory, 40 ... program memory, 41 ... operation unit, SB ... system bus.

Claims (9)

A plurality of light source column groups that are composed of a plurality of semiconductor light emitting elements connected in series and can be driven and controlled in units of columns,
Detecting means for detecting temperatures of different light source row groups among the plurality of light source row groups;
A light source device comprising drive control means for controlling the drive states of the semiconductor light emitting elements of the plurality of light source array groups based on the detection results of the detection means.   The drive control means is configured to detect the semiconductor light emission of the plurality of light source array groups according to the ratio of the temperature rises in the continuous light emission period of the semiconductor light emitting elements for each of the plurality of light source array groups based on the detection result of the detection means. 2. The light source device according to claim 1, wherein the driving state of each element is controlled.   The detecting means detects the temperatures of the semiconductor light emitting elements of the first light source array group and the semiconductor light emitting elements of the second light source array group having different thermal environments among the semiconductor light emitting elements of the plurality of light source array groups. The light source device according to claim 1, wherein: The first row of semiconductor light emitting devices has a higher temperature rise than the second row of semiconductor light emitting devices,
The control means applies the driving current value at the time of stopping the driving to the semiconductor light emitting elements of the second column so that the driving current value at the time of stopping driving is higher than the driving current value at the time of starting driving. 4. The light source device according to claim 3, wherein the driving state of the first semiconductor light emitting element is controlled to be higher than a driving current value. The first row of semiconductor light emitting devices has a higher temperature rise than the second row of semiconductor light emitting devices,
The control means applies the driving current value at the time of driving stop to the semiconductor light emitting elements of the first column so that the driving current value at the time of driving stop becomes lower than the driving current value at the time of driving start. 4. The light source device according to claim 3, wherein a driving state of the second semiconductor light emitting element is controlled so as to be lower than a driving current value.   The drive control means sets in advance a range for limiting the driving conditions of the semiconductor light emitting element, and when the driving condition reaches the range, the drive power increase / decrease relationship that has been controlled and the control target of the semiconductor light emitting element. 4. The light source device according to claim 1, wherein a certain light source array group is inverted. Further comprising cooling means for cooling the semiconductor light emitting elements of the plurality of light source array groups,
The light source apparatus according to claim 1, wherein the detection unit detects temperatures of a plurality of light source array groups having different cooling effects by the cooling unit. A plurality of light source array groups, each of which includes a plurality of semiconductor light emitting elements connected in series and can be driven and controlled in units of columns, a detection unit that detects temperatures of different light source array groups among the plurality of light source array groups, and the above A light source having a drive control unit for controlling the driving states of the semiconductor light emitting elements of the plurality of light source array groups based on the detection result in the detection unit;
An input means for inputting an image signal;
An optical image forming unit that forms an optical image using light from the light source based on an image signal input by the input unit;
A projection apparatus comprising: projection means for projecting the optical image formed by the optical image forming means toward a projection target. A light source control method in an apparatus comprising a plurality of light source column groups that are composed of a plurality of semiconductor light emitting elements connected in series and can be driven and controlled in units of columns,
A detecting step of detecting temperatures of different light source row groups among the plurality of light source row groups,
A light source control method comprising: a drive control step of controlling the drive states of the semiconductor light emitting elements of the plurality of light source array groups based on the detection result in the detection step.

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