JP2007242830A - Display, and method of manufacturing display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the estimating accuracy of the deterioration quantity is low or the manufacturing yield is worse. <P>SOLUTION: A dummy pixel is disposed outside an effective display area. The dummy pixel and the entire vicinity of its light detecting element are covered with a setting dark color adhesive, to surely shut off the outer light and other unexpected lights from mixing in the light of an object to be detected. As the result, the brightness reduction due to the use of the dummy pixel is accurately measured. The measurement result is used for restricting or improving the deterioration of the light emitter, thereby surely resolving the deterioration of the light emitter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The invention described in this specification relates to a technique for arranging dummy pixels to be mounted in order to accurately observe the deterioration state of each pixel constituting an effective display area.
The invention proposed by the inventors has a display device on which dummy pixels are mounted and a side surface as a manufacturing method thereof.

  Flat panel displays are widely used in computer displays, portable terminals, television receivers and other electronic devices. At present, liquid crystal display panels are mainly used for flat panel displays. However, it has been pointed out that the liquid crystal display panel still has a narrow viewing angle and a slow response speed.

For this reason, the appearance of a flat panel display replacing the liquid crystal display panel is expected.
The most promising candidate is an organic EL display panel in which organic EL elements are arranged in a matrix. The organic EL display panel not only has a good viewing angle and responsiveness, but also has excellent characteristics such as no backlight, high brightness, and high contrast.

By the way, it is generally known that the self-luminous elements constituting the organic EL display panel have a characteristic of deteriorating in proportion to the light emission amount and time.
On the other hand, the content of the image displayed on the flat panel display is not uniform. For this reason, deterioration of the light emitter (organic EL element) is likely to partially proceed. For example, the light emitter located in the time display area is more rapidly deteriorated than the light emitters in the other display areas.

The luminance of the light-emitting body that has deteriorated is relatively lowered as compared with the luminance of other display areas. In general, this phenomenon is called “burn-in”. Hereinafter, partial deterioration of the light emitter is referred to as “burn-in”.
Various methods have been proposed for improving “burn-in”. In order to correct burn-in with high accuracy and high performance, it is necessary to correctly detect the actual deterioration state of the light emitter.

Therefore, all the measures for improving the burn-in performed without detecting the deterioration state merely suppress the occurrence of the burn-in.
JP 2003-228329 A JP 2000-132139 A JP 2003-509728 A

  Among these, Patent Literature 1 and Patent Literature 2 disclose a technique for predicting a deterioration state of a light emitter by an integrated value of input display data (gradation value) and correcting the input display data based on the prediction result. That is, these patent documents disclose a technique for correcting burn-in based on a predicted value of deterioration characteristics. For this reason, there is a possibility that burn-in will not be eliminated even after correction based on the prediction result.

  The main factor is that the deterioration characteristics of the light emitter cannot be uniformly determined only by the input gradation value. For example, various conditions such as the surrounding environment, the driving method, the luminance condition, the heat generation condition, and the degree of deterioration have a complicated influence. Moreover, it is necessary to consider individual errors between organic EL display panels. Thus, it is virtually impossible to predict the deterioration state of the light emitter by accurately associating all the conditions.

On the other hand, in the technique disclosed in Patent Document 3, the deterioration characteristics of the light emitter can be detected with high accuracy by the light detection element arranged in the pixel circuit. However, disposing a correction circuit using a photodetection element for each pixel increases the number of transistors per pixel, which is disadvantageous in reducing production yield and increasing resolution.
In addition, the method disclosed in Patent Document 3 has a correction method that only compensates for deteriorated luminance. As a result, the deterioration is promoted, and there is a problem that the limit of correction performance and the luminance half-life come relatively early. is there.

In view of this, the inventors propose a technique in which dummy pixels are arranged outside the effective display area so that the deterioration state in the effective display area can be verified in real time.
At this time, the inventors have, as a display device, (a) an effective display area in which display elements are arranged in a matrix, (b) a dummy pixel arranged outside the effective display area, and (c) a dummy pixel. And (d) a dummy pixel and a curable dark color adhesive layer arranged so as to cover the entire periphery of the light detection element.

  As a method of manufacturing a display device having such a structure, (a) a process of positioning a photodetecting element at a facing position of a dummy pixel arranged outside an effective display area, and (b) a dummy pixel and photodetection And a process of forming a curable dark adhesion layer so as to cover the entire periphery of the element.

  According to the invention proposed by the inventors, the dummy pixel and the photodetecting element are bonded by a hardened dark color adhesive layer, so that the dummy pixel to be received can be received without using a special housing structure or the like. It is possible to realize an environment that can reliably receive only the light. By using this highly reliable detection result for burn-in correction, the burn-in phenomenon can be reliably suppressed or improved.

Hereinafter, embodiments of the self-luminous display device according to the invention will be described.
In addition, the well-known or well-known technique of the said technical field is applied to the part which is not specifically illustrated or described in this specification.
Moreover, the form example demonstrated below is one form example of invention, Comprising: It is not limited to these.

(A) Technology for accurately reflecting fluctuations in light emission characteristics when estimating the deterioration amount The gradation value and the deterioration amount are not necessarily in a proportional relationship. This is because the organic EL element has a characteristic that the light emission characteristic changes due to the characteristic error between panels, the environmental temperature, the light emission temperature of the panel surface, and the like.
For this reason, even if the gradation value is cumulatively added for each pixel, the deterioration amount of the corresponding pixel cannot be accurately estimated.

In view of this, the inventors propose a mechanism for measuring the temporal variation of the light emission characteristics of the organic EL element and reflecting the measurement result in the estimation of the deterioration amount.
FIG. 1 shows the variation of the deterioration rate (rate) due to the difference in the light emission point. FIG. 1 shows temporal changes in light emission luminance in the case where lighting of a light emitter constituting a certain pixel is controlled with a constant gradation value. A curve D _APL represents a deterioration curve when lighting control is performed on a certain pixel (for example, a dummy pixel for measuring deterioration characteristics) with an average gradation value of the entire screen.

An arrow D ₁₀₀ shown in FIG. 1 indicates a progress rate (deterioration rate) of luminance degradation when a gradation value of 100% signal level is given to a pixel. As can be seen by comparing the slope of the arrow D ₁₀₀ with the time point t1 as the base point and the slope of the arrow D ₁₀₀ with the time point t2 as the base point, even when the light emission of a certain pixel is controlled by the same gradation value, If the brightness deterioration is different, the deterioration speed is not the same.

If the deterioration rate is different, the amount of deterioration occurring in the corresponding period is different even if the light emission time length is the same. That is, the correspondence between the gradation value and the deterioration amount changes with the passage of time.
Therefore, the inventors have measured the deterioration state by arranging dummy pixels outside the effective display area, and estimated values of the accumulated deterioration amount differences of the respective pixels constituting the effective display area and the gradation values to be referred to in the calculation. A method for sequentially correcting the deterioration amount conversion table value is proposed.

However, when arranging dummy pixels, it is necessary to consider the possibility of a new problem. This is a problem of erroneous detection of the light detection element.
Usually, the light detection element is disposed at a position opposite to the light emitting surface, and receives only light of a pixel having the light emitting surface. However, there is a possibility that light other than the dummy pixel to be detected enters the light receiving surface.
For example, as shown in FIG. 2, there is a possibility that external light entering from the gap between the glass substrate 1 and the housing 3, light propagating from the display pixel, and light propagating from another adjacent dummy pixel may be mixed.

These events are caused by the fact that the casing 3 covering the outside of the effective display area is intended to protect the corresponding area from the outside, and does not assume dummy pixel arrangement or erroneous detection.
However, even in this case, if the detection purpose is to roughly detect the light amount of the dummy pixel, it does not cause a big problem even if other light source light is mixed.
However, in the system proposed by the inventors, it is necessary to accurately detect the luminance deterioration amount of the dummy pixel. In other words, it cannot be denied that the erroneous detection may adversely affect the burn-in correction process.

As one of countermeasures against this erroneous detection, a method of contriving the structure of the housing 3 itself can be considered. That is, a method of changing the housing structure so that light sources other than the detection target do not affect the light detection element is conceivable.
However, this method requires careful attention to the housing structure. In addition, there is a problem of cost increase due to the change in the housing structure.
Therefore, the inventors adopt a method of covering the entire periphery of the light detection element with a curable dark color adhesive. By using a dark-colored adhesive that can be expected to have a light shielding effect, it is possible to easily and effectively shield leakage light and propagation light that cause erroneous detection.

(B) Preferred Embodiment Hereinafter, an embodiment of an organic EL display device that employs the above-described shading technique and cumulative deterioration information correction technique will be described.
(A) Functional Configuration of Organic EL Display Device FIG. 3 shows a functional configuration example of an organic EL display device equipped with a function for correcting accumulated deterioration information.
3 includes a video signal conversion unit 111, a deterioration amount calculation unit 113, a gradation value / deterioration amount conversion table 115, a cumulative deterioration amount difference calculation unit 117, a cumulative deterioration amount difference accumulation unit 119, and a correction. Amount determining unit 121, self-luminous panel 123, dummy pixel light emission detecting unit 125, deterioration characteristic actual measuring unit 127, dummy pixel cumulative deterioration amount calculating unit 129, average gradation value (APL: average picture level) calculating unit 131, estimation accuracy improvement Part 133 and dummy pixel data determining part 135.

  The video signal converter 111 is a processing device that converts an input display data signal into a corrected display data signal. In the case of this embodiment, the video signal conversion unit 111 executes processing for adding / subtracting a correction value to / from the input display data signal. The correction value is given from the correction amount determination unit 121. Further, the display data signal for the dummy pixel provided from the dummy pixel data determining unit 135 is multiplexed with the corrected display data signal. The corrected display data signal is given to the deterioration amount calculation unit 113, the self-luminous panel 123, and the APL calculation unit 131.

  The deterioration amount calculation unit 113 is a processing device that calculates the deterioration amount of each pixel associated with image display based on the gradation value corresponding to each pixel. In this embodiment, the gradation value / degradation amount conversion table 115 is used. Here, the pixel includes both a pixel in the effective display area and a dummy pixel. Therefore, the deterioration amount calculation unit 113 calculates the estimated deterioration amount for each pixel in the effective display area and the estimated deterioration amount for the dummy pixel.

  FIG. 4 shows an example of the gradation value / degradation amount conversion table 115. The gradation / degradation amount conversion table 115 stores all gradation values that can be taken by the input display data signal and the corresponding degradation amounts in association with each other. The deterioration amount R is given as a product of the deterioration rate (deterioration rate) corresponding to each gradation value and the light emission period t. The light emission period t may be fixed or variable.

The cumulative deterioration amount difference calculation unit 117 is a processing device that calculates a cumulative value of the deterioration amount difference newly generated between a certain reference pixel and each pixel in the effective display area. The reference pixel may be a real pixel or a virtually set pixel. The former includes, for example, a pixel having the smallest cumulative deterioration amount in pixel units and a pixel having the largest cumulative deterioration amount in pixel units. The latter includes a virtual pixel that emits light at an average gradation value within one frame. In the case of this embodiment, the reference pixel is assumed to be a pixel whose light emission is controlled with the average gradation value of the entire screen.
An estimated deterioration amount corresponding to each pixel in the effective display area is given from the deterioration amount calculation unit 113.

The cumulative deterioration amount difference accumulation unit 119 is a storage area or storage device that stores a cumulative deterioration amount difference of each pixel with respect to a reference pixel. The cumulative deterioration amount difference represents the degree of progress (whether advanced or delayed) and the degree of progress of a certain pixel with respect to a reference pixel.
The correction amount determination unit 121 is a processing device that determines a correction value corresponding to each pixel based on a cumulative deterioration amount difference.
FIG. 5 shows an internal configuration example of the correction amount determination unit 121. The correction amount determination unit 121 includes an estimated error amount correction unit 1211 and a correction amount calculation unit 1213.

Based on the estimated error rate α given from the estimated accuracy improving unit 133, the estimated error amount correcting unit 1211 calculates the actual accumulated difference amount of each pixel calculated by referring to the gradation value / degradation amount conversion table 115. This is a processing device that uniformly corrects the accumulated deterioration amount difference.
In the case of this embodiment, the estimated error amount α is given as a 100-percentage value by the estimation accuracy improvement unit 133. Therefore, the accumulated error amount can be calculated by multiplying the accumulated deterioration amount by the estimated error amount α. The correction principle will be described later.

The correction amount calculation unit 1213 is a processing device that calculates a correction amount corresponding to each pixel based on the corrected accumulated deterioration amount difference. The correction amount determination method by the correction amount calculation unit 1213 includes a method of determining a correction value so as to eliminate the accumulated deterioration amount difference, and a method of determining the correction value so that the visual luminance difference is uniform.
As described above, the correction amount determination unit 121 determines a correction value based on a value obtained by removing the cumulative error amount from the cumulative deterioration amount difference.

The self light emitting panel 123 is a display device in which light emitters (self light emitting elements) are arranged in a matrix on a base. In the case of this embodiment, an organic EL element is used as the light emitter.
FIG. 6 shows a planar configuration example of the self-luminous panel 123. Note that FIG. 6 is mainly shown from the viewpoint of pixel arrangement, and the drive circuit and other peripheral circuits are omitted.
In the case of the self-luminous panel 123 shown in FIG. 6, one dummy pixel 1233 is arranged at the lower outer portion of the effective display area 1231.

The effective display area 1231 is an area that can be observed from the outside, and displays an image corresponding to the input image data signal.
On the other hand, the dummy pixel 1233 is an area used for measurement of the deterioration state, and is shielded from light so that the emitted light is not observed from the outside.
In FIG. 6, one pixel on the display in which basic pixels corresponding to the basic emission colors of red (R), green (G), and blue (B) are integrated is represented by one square. As described above, in this embodiment, three colors of red (R), green (G), and blue (B) are set as basic emission colors.

FIG. 7 shows a structural example of the dummy pixel 1233. In FIG. 7, the outer edges of the light detection element 12331 that detects the light emission luminance of the dummy pixel 1233 and the curable dark adhesive 12333 that seals the whole are indicated by broken lines.
FIG. 8 shows a cross-sectional layer structure of the dummy pixel portion. As shown in FIG. 8, the light detection element 12331 has a light receiving surface disposed immediately above the dummy pixel 1233, and the surface thereof is covered with the curable dark color adhesive 12. The reason why the curable adhesive is used is to prevent the light shielding state from changing after shipment.

The curable dark color adhesive 12 can be a general adhesive used for fixing electric and electronic parts. However, the condition is that it is not transparent (not pass light). For example, an adhesive such as silicone rubber, polyester resin, or chloroprenecom is used as it is. Specifically, SC901 / SC905 (silicone type), SC608Z2 (polyester type), and SC12N (chloroprene type) manufactured by Sony Chemical are used.
FIG. 9 shows an example of a manufacturing process. First, as shown in FIG. 9A, a display panel in which dummy pixels 1233 are formed outside the effective display region 1231 is prepared.

  Next, as illustrated in FIG. 9B, the light detection element 12331 is disposed directly above the dummy pixel 1233, and the light receiving surface thereof is disposed so as to cover the light emitting surface of the dummy pixel 1233. In this state, the light detection element 12331 is fixed to the surface of the dummy pixel 1233 as shown in FIG. Thereafter, as shown in FIG. 9D, a curable dark adhesive 12333 is applied so as to cover the entire periphery of the dummy pixel 1233 and the light detection element 12331. Thereafter, the display device is completed by hiding the outer surface of the effective display area of the display panel having these structures with a casing.

In use, each basic pixel constituting the dummy pixel 1233 is individually controlled to emit light using the blanking period of the input display data signal.
Further, as shown in FIG. 6 described above, this can be realized by arranging only one data drive line and one gate drive line for driving the dummy pixel 1233.
As described above, the dummy pixel 1233 can be realized with the same structure as each pixel in the effective display area 1231 and does not require a dedicated or large-scale driving circuit.

  Further, the structure of the dummy pixel 1233 may be the same as that of the pixel circuit corresponding to each pixel of the effective display area 1231. That is, it is composed of a selection transistor and a drive transistor. Therefore, the difficulty in production of the display panel itself and an increase in cost hardly occur.

  The dummy pixel light emission detection unit 125 corresponds to a light detection element 12331 that detects visible light output from the dummy pixel 1233 and converts it into an electrical signal. An arbitrary detection sensor is applied to the light detection element 12331. In general, the light detection element 12331 is preferably a visible light sensor using an amorphous silicon semiconductor. Light amount information detected as a current value is amplified, converted into a voltage value, and output as a detection signal.

  The degradation characteristic measurement unit 127 provides the dummy pixel data determination unit 135 with a timing (measurement timing) for detecting the degradation state of the dummy pixel 1233 and a display data signal (gradation value) applied to the dummy pixel 1233 at the detection timing. It is a processing device. In the case of this embodiment, the detection of the deterioration state is executed at a constant cycle (every fixed number of frames). Further, the detection of the deterioration state is always performed using the same gradation value. By illuminating the dummy pixel 1233 with the same gradation value, it is possible to detect the deterioration of the light emitter as the transition of the light emission luminance.

Note that the gradation value given to the dummy pixel data determination unit 135 by the deterioration characteristic measurement unit 127 may be set for each RGB, or the same value may be used for any of RGB. For example, a 100% gradation value (“255” when the gradation is 8 bits) is used. Incidentally, the same gradation value is given to the dummy pixels corresponding to the same emission color.
In addition, the deterioration characteristic actual measurement unit 127 generates a difference ΔR between the light emission luminance detected in the initial state and the light emission luminance detected this time within the actual measurement period (between the initial detection timing of the actual measurement period and the current detection timing). It also functions as a processing device that is given to the estimation accuracy improvement unit 133 as accumulated deterioration information.

It should be noted that the degradation characteristic measurement unit 127 also gives the estimation accuracy improvement unit 133 the time required for degradation of the dummy pixel 1233 (in this example, a fixed value) and the average gradation value.
However, when the deterioration characteristic measurement unit 127 calculates the deterioration rate between the actual measurement timings, only the calculation result is given to the estimation accuracy improvement unit 133. The deterioration rate is given as a deterioration amount per unit time. Therefore, ΔR can be obtained by dividing by the number of frames in the actual measurement period.

The dummy pixel cumulative deterioration amount calculation unit 129 is a processing device that calculates a cumulative value of estimated deterioration amounts calculated for dummy pixels for each basic light emission color (for each RGB). The estimated deterioration amount in units of frames corresponding to each dummy pixel is calculated by the deterioration amount calculation unit 113.
The APL calculation unit 131 calculates a frame-unit average gradation value for the corrected display data signal for each RGB pixel, and calculates an average value of the average gradation value for each RGB pixel calculated in the past (hereinafter, “average APL value”). And a processing device that executes a process of calculating.

The average gradation value for each RGB pixel calculated for each frame is given to the dummy pixel data determination unit 135. The average APL value is given to the estimation accuracy improvement unit 133.
The estimation accuracy improving unit 133 improves the accuracy of the gradation value / deterioration amount conversion table 115 used for calculating the deterioration amount, and the processing function for improving the accuracy of the accumulated deterioration amount difference used for calculating the correction amount. And a processing device.

FIG. 10 shows an example of the internal configuration of the estimation accuracy improvement unit 133. The estimation accuracy improvement unit 133 includes an actually measured deterioration rate calculation unit 1331, a table update unit 1333, and an estimation error rate calculation unit 1335.
The actually measured deterioration rate calculation unit 1331 recalculates the current values of the deterioration rates corresponding to all the gradation values based on the deterioration rate actually measured for each of the RGB values of the dummy pixel 1233 and the average APL value within the actually measured period. A process and a process of calculating a deterioration amount corresponding to each gradation value based on the deterioration rate calculated for all gradation values are executed.

The table updating unit 1333 executes processing for updating the gradation value / degradation amount conversion table 115 in which the gradation value and the deterioration amount are associated based on the calculation result.
The estimated error rate calculation unit 1335 compares the degradation amount ΔR actually measured for each of the RGB values of the dummy pixel 1233 with the cumulative degradation amount calculated by the dummy pixel cumulative degradation amount calculation unit 129, and estimates the estimated error amount with respect to the actual degradation amount ΔR. α is calculated in 100 minutes. The calculated estimated error amount α is given to the correction amount determination unit 121.

  The dummy pixel data determination unit 135 is a processing device that determines dummy pixel data (gradation value) to be given to the dummy pixel 1233. For example, during a period when the deterioration state of the dummy pixel 1233 is not actually measured, the dummy pixel data determination unit 135 determines the average gradation value of the entire effective display area as dummy pixel data. The average gradation value is given from the APL calculation unit 131. Further, for example, at the timing of actually measuring the deterioration state of the dummy pixel 1233, the dummy pixel data determining unit 135 determines the fixed gradation value for detecting the deterioration state given from the deterioration characteristic measuring unit 127 as dummy pixel data.

(B) Processing Operation Next, the processing operation executed by the organic EL display device 11 will be described.
When an input image is displayed, an input display data signal corresponding to the organic display region 1231 is subjected to correction processing by the video signal conversion unit 111 and then provided to the self-luminous panel 123 as a corrected display data signal.

The dummy pixel data determination unit 135 supplies the average gradation value calculated for each frame to the video signal conversion unit 111 as a display data signal for the dummy pixel, unless the detection period of the deterioration state of the dummy pixel 1233 is detected. That is, the same display data signal is given to the two dummy pixels 1233.
As a result, the R pixel dummy pixel 1233 is controlled to emit light with the average gradation value of all the R pixels constituting the immediately preceding frame. Further, the light emission of the dummy pixel 1233 for the G pixel is controlled by the average gradation value of all the G pixels constituting the immediately preceding frame. Similarly, the light emission of the dummy pixel 1233 for the B pixel is controlled by the average gradation value of all the B pixels constituting the immediately preceding frame.

  FIG. 11 shows an example of a display data signal for the dummy pixel 1233 output from the dummy pixel data determination unit 135 to the video signal conversion unit 111. As a result, the dummy pixels 1233 arranged outside the effective display area emit light in exactly the same state as the average RGB pixels in the effective display area 1231. That is, if an individual error between pixels is ignored, the deterioration proceeds in the same manner as in the effective display area.

  Eventually, when it is time to detect the deterioration state of the dummy pixel 1233, the dummy pixel data determination unit 135 converts the gradation value for inspection given from the deterioration characteristic measurement unit 127 as a display data signal for the dummy pixel to convert the video signal. To part 111. FIG. 11 shows a state in which a gradation value of 100% is given to the detection timing.

The deterioration characteristic actual measurement unit 127 inputs the light emission luminance value detected by the dummy pixel light emission detection unit 125 at this detection timing.
FIG. 12 shows an example of transition of detection results. In the figure, the luminance indicated by a black circle is the detected value. As shown by connecting the black circles with a solid line, it can be seen that the detected light emission luminance decreases despite the fact that light is emitted at the same 100% gradation value. However, FIG. 12 exaggerates the decrease in luminance, and it is gradually reduced.

The degradation characteristic actual measurement unit 127 calculates a difference ΔR from the first detection value in the actual measurement period every time the emission luminance of the dummy pixel is newly detected.
FIG. 12 shows how the difference ΔR is obtained between the light emission times t0 and t6.
When the difference ΔR is obtained, the estimation accuracy improving unit 133 can calculate the change rate of the deterioration amount generated within the actual measurement period, that is, the deterioration rate.
FIG. 13 shows the calculation principle of the deterioration rate. FIG. 13 shows a case where the detection luminance at the first detection timing t (n) in the actual measurement period is 100% and the detection luminance at the current detection timing t (m) is 85%.

Therefore, the difference ΔR is 15%. Further, assuming that the number of frames between the detection timings t (n) and t (m) is F, the estimation accuracy improving unit 133 calculates the deterioration rate corresponding to the RGB pixels as ΔR / F, respectively.
Thereafter, the estimation accuracy improvement unit 133 acquires the average APL value for each RGB pixel corresponding to the actual measurement period from the APL calculation unit 131. In the case of FIG. 13, the average gradation value is 100 in terms of gradation value (when the gradation value is 8 bits).

Thus, the relationship between the actually measured deterioration rate within the actual measurement period and the average APL value during the actual measurement period is determined. Since this correspondence is an actual measurement value, it reflects all the contents of the display image, the usage environment, and the like. That is, the correspondence between the average APL value and the deterioration rate (deterioration amount) is accurately reflected.
However, the actually measured correspondence is only one of 256 correspondences (when gradation is given by 8 bits).
Therefore, in order to accurately predict the deterioration rate (deterioration amount) corresponding to all input gradation values, it is necessary to calculate the current deterioration rate (actual deterioration rate) for all other gradation values. .

Therefore, the estimation accuracy improving unit 133 (actually measured deterioration rate calculating unit 1331) calculates this correspondence using the basic correspondence between the gradation value and the deterioration rate shown in FIG. The basic correspondence relationship is referred to because the measured correspondence relationship and other correspondence relationships basically maintain the relationship shown in FIG. 14 even if the actual measurement value of the deterioration rate corresponding to the gradation value changes. Because it is. The basic correspondence shown in FIG. 14 is stored in the measured deterioration rate calculation unit 1331 as basic table information.
FIG. 15 shows the principle of calculation of the deterioration rate corresponding to all gradation values by the actually measured deterioration rate calculation unit 1331.

Figure 15 is actually measured relationship is 100 gradation values (when the gradation is expressed by 8 bits) represents the actual deterioration rate at that time as X _100. At this time, the actually measured deterioration rate X _a corresponding to an arbitrary gradation value a is obtained by multiplying the actually measured deterioration rate X ₁₀₀ by the ratio α _a / α ₁₀₀ between the deterioration rates specified through the basic table curve shown in FIG. Can be calculated.
As a result, a new correspondence relationship amplified by the deterioration rate (degradation speed) is calculated while maintaining the basic correspondence relationship between the gradation values.

When the estimated deterioration rate X _a corresponding to all the gradation values is calculated, the estimation accuracy improving unit 133 updates the gradation value / deterioration amount conversion table 115 with these values. The deterioration amount is calculated as a product of the actually measured deterioration rate _Xa and the light emission period t. FIG. 17 shows a state where the deterioration rate is updated for all the gradation values constituting the gradation value / degradation amount conversion table 115.
Incidentally, the shorter the detection period (cycle) is, the more generally it can cope with a sudden change in the tendency of the display image. Therefore, the error of the predicted deterioration amount can be reduced accordingly.

In parallel with the update process of the gradation value / degradation amount conversion table 115, the estimated error rate calculation unit 1335 calculates the estimated error rate α. The estimation error is a deterioration amount difference caused by accumulation of errors generated when the deterioration amount is predicted. Further, the estimated error rate is a 100% error ratio between the estimated deterioration rate and the actual luminance deterioration rate.
FIG. 18 shows the correspondence. In the figure, the thick line corresponds to the change in the actual luminance deterioration rate b, and the thin line corresponds to the change in the estimated luminance deterioration rate a. The estimated luminance deterioration rate is a deterioration amount calculated by the deterioration amount calculation unit 113.

  FIG. 18 shows the luminance deterioration rate as a percentage of 100 with respect to the initial value. In this case, the estimated error rate α is represented by b / a%. Accordingly, if the actual luminance deterioration rate (amount) is ahead of the estimated luminance rate (amount), the estimated error rate α is a value exceeding 100%. On the other hand, if the actual luminance deterioration rate (amount) is later than the estimated luminance rate (amount), the estimated error rate α is less than 100%. If the actual luminance deterioration rate (amount) matches the estimated luminance rate (amount), the estimated error rate α is a value of 100%.

Therefore, the estimated error rate calculation unit 1335 divides the accumulated deterioration amount calculated for the dummy pixel with respect to the actually measured deterioration rate by the actually measured deterioration amount ΔR to calculate the estimated error rate α (= b / a).
The estimated error rate α is output to the correction amount determination unit 121, and is multiplied by the accumulated deterioration amount difference which is a premise for determining the correction amount.

FIG. 19 illustrates the principle of correcting an error included in the accumulated deterioration amount difference by multiplication of the estimated error rate α. Assume that the estimated error rate α has the same relationship with all the deterioration rates X _{0 to} X ₂₅₅ .
In this case, the actual accumulated deterioration amount difference (rate) β2 is calculated as an estimated error rate α (= b / a) to the estimated and calculated accumulated deterioration amount difference (rate) β1. That is, β2 = (b / a) × β1 is calculated.
As described above, since the correction amount is determined in a state where the influence of the error is removed, the correction accuracy is remarkably improved.

(C) Effect As described above, in the organic EL display device according to this embodiment, one dummy pixel 1233 is arranged outside the effective display region 1231, and the average of the input display data signals corresponding to the respective basic emission colors. The light emission is controlled by the gradation value.
Thereby, the deterioration characteristic of the dummy pixel 1233 can be matched with the deterioration characteristic in the effective display area.

By the way, the periphery of the dummy pixel 1233 and the light detection element 1231 is completely covered with the curable dark color adhesive 12333. Therefore, only the light of the dummy pixel to be detected is reliably incident on the light detection element 1231.
In this way, by updating the relationship between the gradation value and the deterioration rate (deterioration amount) at the current time point based on the actual measurement value of the accumulated deterioration amount with increased reliability of the measurement value, the signal is also displayed on the panel structure. The prediction accuracy of deterioration information can be improved within a practical range in terms of processing.

At this time, the deterioration rate (deterioration speed) corresponding to all the gradation values can be updated only by actually measuring one correspondence.
For this reason, it is possible to significantly reduce the amount of information to be grasped in advance experiments, and in this respect also, it is possible to realize a significant reduction in manufacturing costs.
Further, in the organic EL display device according to this embodiment, a structure for detecting the light quantity for all the pixels is not required even when the screen size is increased, and one dummy pixel 1233 to be arranged is also an extension of the normal panel process. Can be created on line (with very little change to the panel process).

That is, the production difficulty of the display panel itself is not increased and the cost is hardly increased. Thus, it is also effective in terms of manufacturing technology.
Further, the shape of the curable dark color adhesive applied for the purpose of removing the influence of light other than the dummy pixels to be detected can be freely changed until it is cured. For this reason, it is not necessary to pay close attention to the construction of the light-shielding structure of the light-emitting element portion, and the housing having the conventional specifications can be used as it is. This is also effective in reducing the manufacturing cost of the display panel.

(C) Other Embodiments (a) In the embodiment described above, the case where only one dummy pixel 1233 is arranged outside the effective display area has been described. In this case, the curable dark color adhesive is used mainly for the purpose of removing the influence of external light entering from the gap between the glass substrate and the housing.
However, the present invention can also be applied to a case where two or more dummy pixels are arranged side by side. FIG. 20 shows a case where two dummy pixels 1233 are arranged side by side. In this case, the curable dark color adhesive exhibits an additional effect of blocking the propagation light from the adjacent dummy pixels.

When a plurality of dummy pixels are arranged, the average value of the luminance values detected by the plurality of dummy pixels is obtained, and the estimated accuracy of the accumulated deterioration amount difference and the conversion table update processing are executed with this value. By doing so, the correction accuracy can be further improved by eliminating the influence of the individual error of the dummy pixel.
Needless to say, the arrangement position of the dummy pixels is arbitrary.

(B) In the above-described embodiment, the case where the basic light emission colors are three colors of RGB has been described. However, the basic light emission colors can be applied to a case where there are four or more colors including complementary colors.
(C) In the above-described embodiment, the color generation form of the basic light emission color has not been described. However, an organic EL element having a different light emitting element material for each basic light emission color may be prepared, and a color filter method or a color conversion method may be used. It may be used to generate a basic emission color.

(D) In the above-described embodiment, the organic EL display panel is illustrated as an example of the self-luminous display device, but the present invention can also be applied to other self-luminous display devices. For example, the present invention can be applied to FED (field emission display), inorganic EL display panel, LED panel, and the like.

(E) In the above-described embodiment, the organic EL display device 11 that has the function of updating the gradation value / deterioration rate conversion table 115 and the function of correcting the estimation error of the accumulated deterioration amount difference has been described.
However, these functions may be implemented as a part of an image processing apparatus equipped with a self-luminous display device. For example, the update function of the gradation value / deterioration rate conversion table 115 includes a video camera, a digital camera, and other imaging devices (including not only a camera unit but also a configuration integrated with a recording device), an information processing terminal. (A portable computer, a mobile phone, a portable game machine, an electronic notebook, etc.), a game machine, a printer device, etc. may be mounted.

(F) In the above-described embodiment, the organic EL display device 11 that has the function of updating the gradation value / deterioration rate conversion table 115 and the function of correcting the estimation error of the accumulated deterioration amount difference has been described.
However, these functions may be installed in an image processing device that supplies an input display data signal to a self-luminous display device or an image processing device equipped with the self-luminous display device. In other words, a method may be employed in which the light emission luminance and deterioration information of the dummy pixels are taken into the self device from the self light emitting display device.

(G) In the above-described embodiment, the function of updating the gradation value / deterioration rate conversion table 115 and the function of correcting the estimation error of the accumulated deterioration amount difference have been described from the viewpoint of the functional configuration. It can be realized as hardware or software.
Further, not only all of these processing functions are realized by hardware or software, but some of them may be realized by using hardware or software. That is, a combination of hardware and software may be used.
(H) Various modifications can be considered for the above-described embodiments within the scope of the gist of the invention. Various modifications and applications created or combined based on the description of the present specification are also conceivable.

It is a figure explaining the fluctuation | variation with time of a deterioration rate. It is sectional drawing explaining propagation | transmission of the light which causes a misdetection. It is a figure which shows the system structural example of an organic electroluminescent display apparatus. It is a figure which shows the structural example of a gradation value / degradation amount conversion table. It is a figure which shows the internal structural example of the correction amount determination part. It is a figure which shows the plane structural example of a display panel. It is an enlarged view of a dummy pixel. It is a figure explaining the cross-sectional structure of the area | region part which arranges a dummy pixel. It is a figure which shows the manufacturing process of a display panel. It is a figure which shows the internal structural example of an estimation precision improvement part. It is a figure which shows the example of a display data signal for dummy pixels. It is a figure which shows the example of transition of the degradation characteristic about a dummy pixel. It is a figure explaining the measurement principle of a deterioration rate. It is a figure which shows the example of a basic correspondence relationship referred at the time of calculation of an actual deterioration rate. It is a figure which shows the calculation principle of the actual deterioration rate which referred the basic correspondence. It is a figure explaining the relationship between the deterioration rates on a basic table. It is a figure explaining the update operation | movement of a gradation / degradation amount conversion table. It is a figure explaining an estimated deterioration rate. It is a figure explaining the correction process of the accumulation degradation amount difference by an estimation error rate. It is a figure which shows the other planar structural example of a display panel.

Explanation of symbols

121 correction amount determination unit 125 dummy pixel light emission detection unit 127 deterioration characteristic measurement unit 129 dummy pixel cumulative deterioration amount calculation unit 133 estimation accuracy improvement unit 1211 estimation error amount correction unit 1213 correction amount calculation unit 12333 curable dark color adhesive 1331 actual deterioration Rate calculation unit 1333 Table update unit 1335 Estimated error rate calculation unit 135 Dummy pixel data determination unit

Claims (2)

An effective display area in which display elements are arranged in a matrix; and
Dummy pixels disposed outside the effective display area;
A photodetecting element positioned to face the dummy pixel;
A curable dark color adhesive layer disposed so as to cover the entire periphery of the dummy pixel and the light detection element. A process of positioning the light detection element at the facing position of the dummy pixel disposed outside the effective display area;
And a process of forming a curable dark adhesive layer so as to cover the entire periphery of the dummy pixel and the light detection element.

Images